At stock boost levels, only about 5 lbs, It has about 320-335 RWH, We "hope" to get about 390 RWH with about 7-8lbs of boost, but I think we will only see about 370-375 RWH. As for performance she runs great once she can hook up, but till then all she does is throw rubber everywhere. Would make a great drifter As for the install, There were soooo many tools we had to cut and modify to install the kit. BIGGEST problem is lack of room. IF and I mean IF I were to do this again, removing the engine will make life awhole lot better. Now I know why everywhere we checked wanted $2000.00+ for labor to install the kit