I've read reviews about these leaking on another site due to the bolts being to long but mine leaked out the fill plug. The shop said the threads on the fill plug allowed fluid to pass through so they had to put some teflon tape to prevent it from leaking.
Yes, this fits under the stock location of the panhard bar. Most of the diff covers for the S197 I've seen have required a bar relocator to clear the machined cover. As far as functionality goes, it holds oil and looks cool... I don't usually launch the car hard but it is a great piece of mind to have the support. Fill and drain plugs are a bonus.
I installed this on a 2011 V6 Mustang. It fit with my aftermarket panhard bar without relocation. The Drake cover looks good and is much more sturdy than the stock cover. I also like the axle bearing cap screws. I plan to make some hard launches at the drag strip. I am very happy with the Drake unit. Plus the price is right!