2002+ Subaru WRX/STI Group N Pitch Stop Mount by Subaru OEM (D1040FE000)
This is a quality, genuine STI group N piece which will help prevent movement of the engine. If delivering more power to the wheels is your goal, this piece is one of many that will help you accomplish that task.
This is a subtle improvement over the stock pitch stop in the 2015+ WRX, which is exactly what I wanted. I haven't noticed any increased harshness or vibration, the engine noise is a little louder but it's deep and sounds nice. Drive feel is also slightly better, I notice a little less bucking when shifting, especially downshifting.