Best S650 Mustang Mods

The S650 Mustang offers plenty of performance and personality straight from the factory, but there's still room to make it your own. From the EcoBoost to the GT and Dark Horse, owners can choose simple bolt-on upgrades or build a more specialized street or track car.

The best S650 Mustang mods depend on how you drive and what you want to change. An upgraded air filter or a few styling details can be an inexpensive starting point. Exhaust, suspension, and wheel upgrades can make a bigger difference in how the car looks, sounds, and feels. Here are our top modifications to consider, along with a few tips for choosing the right setup.

S650 Mustang Air Filter and Cold Air Intake Upgrades

One of the easiest places to start modifying your S650 is the intake system. You don't have to replace the entire intake assembly to make a change, and the right choice depends on your budget and performance goals.

High-Flow Air Filters

A replacement high-flow air filter is a simple, relatively inexpensive upgrade that fits inside the factory intake housing. A less restrictive filter may improve airflow, and many aftermarket filters are reusable, so you can clean and reinstall them rather than replacing them at every service interval. Don't expect an air filter alone to deliver a dramatic horsepower increase.

Cold Air Intakes

A complete cold air intake replaces more of the factory intake path and may use revised tubing, an airbox, and a high-flow filter. Depending on the system, it can change the intake sound and throttle response and provide additional airflow. Actual performance results vary by engine and product.

Choose an intake designed for your specific S650 engine and check whether the manufacturer requires additional tuning. For a modest daily-driver upgrade, a drop-in filter may be enough. If you're planning additional engine modifications, a complete intake could be a better starting point. Read our cold air intake guide for more information.

Intercoolers for the EcoBoost

For EcoBoost owners planning a more involved performance build, an upgraded intercooler is another option worth considering. Intercoolers cool compressed intake air from the turbocharger. An upgraded unit may help manage intake temperatures during repeated acceleration or demanding driving, although the results depend on the setup. This is an additional option from our original guide rather than a modification featured in the new video.

S650 Mustang Exhaust Upgrades

Exhaust modifications are a popular way to change your Mustang's character. The right system can make the car sound deeper, sharper, or louder, but more volume isn't always better for a daily driver or a car you take on long trips. Consider sound level, cabin drone, and your car's factory exhaust configuration before choosing a kit.

Axle-Back Exhaust Systems

An axle-back exhaust replaces the rear portion of the factory system, typically including the mufflers and tips. It's a good choice if you mainly want a different exhaust tone without replacing as much piping. Installation requirements vary by kit, and some setups require cutting the factory pipes.

Cat-Back Exhaust Systems

A cat-back exhaust replaces a larger section of the system behind the catalytic converters. It offers more flexibility to change exhaust tone and flow, although horsepower gains are not guaranteed. This is a good option for owners who want a more substantial change to the sound of their GT, EcoBoost, or Dark Horse.

Resonator Deletes

A resonator delete is a simpler option for changing exhaust sound without purchasing a complete exhaust system. It removes or replaces the factory resonator section, depending on the configuration. Expect a different tone and potentially more volume or drone, so listen to examples of the setup you're considering before making the change.

Fitment tip: If your Mustang has factory active exhaust, make sure the replacement components explicitly support that system and preserve the functions you want to keep. Also check local noise and emissions requirements.

S650 Mustang Suspension Upgrades

Suspension upgrades can change your S650's stance and how it responds through corners. A comfortable street setup will have different priorities from a Mustang built primarily for road-course use, so consider ride quality and handling together.

Lowering Springs

Lowering springs replace the factory springs to reduce ride height. They're one of the more affordable ways to give the S650 a lower, more aggressive stance and can help reduce body roll when paired with an appropriate suspension setup. The amount of drop and resulting ride quality depend on the spring design and the rest of the suspension.

After lowering your Mustang, check alignment and suspension geometry. Make sure the new ride height leaves adequate clearance for your wheels, tires, and normal driving conditions.

Shocks, Struts, Sway Bars, and Control Arms

As your handling goals become more specific, consider matched shocks and struts, upgraded sway bars, and control arms. These parts can help manage body motion and suspension behavior, but they work best when selected as a complete setup rather than as unrelated upgrades.

Coilovers

Coilovers offer a more adjustable approach than conventional lowering springs. Depending on the kit, you can adjust ride height and damping to better suit your driving style. They're worth considering for owners who want greater control over their suspension setup, particularly for regular track use, though they generally cost more than a basic spring kit.

S650 Mustang Wheel and Tire Upgrades

Wheels and tires can make an immediate visual difference, but they also affect traction, steering response, and ride quality. Choosing the right tires is especially important for performance builds because extra engine power is only useful when the tires can put it to the pavement.

Wheel Spacers

Wheel spacers move the wheels outward from the hubs and can help fine-tune the appearance of your existing setup. Choose quality spacers that are appropriate for your wheel and hub configuration, and verify stud engagement, fastener requirements, and clearance before installation.

Aftermarket Wheels and Performance Tires

Aftermarket wheels give you more choices in diameter, width, offset, and finish. Black, bronze, and silver wheels each create a different look, but fitment matters more than color. Verify brake clearance, tire sizing, suspension clearance, and the wheel's specifications for your particular GT, EcoBoost, or Dark Horse.

If you want better grip, start by choosing tires suited to your driving conditions. A road-course build may prioritize cornering performance, while a drag-oriented setup may need a different tire compound and size. A larger wheel diameter alone doesn't guarantee better handling.

S650 Mustang Exterior Styling Mods

Not every S650 modification needs to increase power or change handling. Small styling upgrades can make your Mustang look noticeably different without committing to a full body kit.

Badges, Emblems, and Exterior Accents

Swapping badges or emblems and adding carefully chosen trim accents can give the exterior a more personalized look. These are approachable first modifications if you're working with a smaller budget or want to keep most of the factory styling.

Headlights, Taillights, and Side Markers

Lighting changes can make a big visual impact. Depending on your Mustang and available parts, you can consider aftermarket headlights, taillights, sequential lighting options, and side markers. Confirm fitment and road-use legality before installing tinted or modified lighting components.

Spoilers, Splitters, Side Skirts, and Diffusers

For a more aggressive appearance, consider a rear spoiler, front splitter or lip, side skirts, diffuser, or grille upgrade. You can change the look of the car with a few coordinated pieces rather than replacing every exterior panel.

Some aerodynamic parts are designed to affect airflow at speed, but the results depend on the design and installation. Our guide to Mustang spoilers, wings, and splitters explains the differences. For more extensive exterior projects, see our widebody Mustang guide.

Jacking Rails

Jacking rails aren't a styling mod, but they're a useful addition if you work on your Mustang regularly. A compatible set provides designated lifting contact areas and can make routine maintenance more convenient. Always follow the vehicle and rail manufacturer's lifting and support instructions.

S650 Mustang Oil Separators

An oil separator is a less visible modification that may appeal to S650 owners who frequently drive hard or take their cars to the track. It captures some of the oil mist carried through the crankcase ventilation system before that vapor returns to the intake tract.

Unlike an intake or exhaust, an oil separator isn't primarily intended to increase horsepower. It's an engine-supporting modification that requires routine attention. Check the collection canister regularly, with the video recommending inspection approximately every 1,000 to 3,000 miles, and empty it as directed by the manufacturer. Service intervals can vary with driving conditions and the particular separator.

S650 Mustang Interior Mods

Interior upgrades are another way to personalize your Mustang, particularly if you spend most of your time driving it on the street. These recommendations from our original guide remain useful even though they aren't featured in the new video.

Short-Throw Shifters

For a compatible manual-transmission Mustang, a short-throw shifter reduces the distance the shift lever travels between gears. It can make shifts feel quicker and more direct without changing engine output. Confirm transmission and model compatibility before ordering.

Shift Knobs

A replacement shift knob is a simple way to change the look and feel of your cabin. Choose a shape, weight, and finish that feels comfortable in your hand and fits your shifter.

Floor Mats

Replacement floor mats protect the carpeting from dirt, water, and everyday wear. They're an inexpensive way to keep the interior looking clean, especially if your S650 is a daily driver. Use mats designed for your vehicle that won't interfere with the pedals.

Build Your S650 Mustang Around How You Drive

The best Mustang mods aren't necessarily the most expensive or the loudest. A daily driver may benefit most from a comfortable suspension setup, an exhaust tone you enjoy, and a few appearance upgrades. A drag-focused car may prioritize traction, tires, and power, while a road-course build may put more emphasis on suspension, braking, and cooling.

Start with the part of your S650 you most want to change. A high-flow filter, exhaust upgrade, lowering springs, wheels, or a few styling details can be a worthwhile first step. Then build on those changes as your goals become clearer.

If you're interested in learning more about this awesome car, check out this article we wrote on five S650 Mustang easter eggs.

Check out the rest of our generational Mustang Mod guides for even more Mustang parts recommendations:

• Classic Mustang Mod Guide
• Fox Body Mustang Mod Guide
• 1994-1998 Mustang Mod Guide
• New Edge Mustang Mod Guide
• 2005-2010 Mustang Mod Guide
• 2011-2014 Mustang Mod Guide
• S550 Mustang Mod Guide

Image Credit: Ford