This seemed a brilliant idea when I bought one, harness performance without a roll bar, and easy access to the back seat. The execution is a bit different.
Problems:Installation is involved, you have to remove your front seat, possibly the rear seat,and the rear interior panel. Unless you like the gaping hole, you will need to find a cover or snap in plug for the upper mounting point of the stock belt. Your seat belt light will remain lit at all times. The enertia reel must be carefully aligned to work, and the angle is not ideal, I would recommend a harness bar. The buckle is fragile. Finally, after a year, my lap belt webbing is worn smooth, the slider quickly comes loose so constant tightening is need to be safe, especially on track days.