Re: RENNtech Performance Package 1
The best performance upgrade is made by evosport. I have their underdrive pulleys for my mercedes 3.2L V6 and they really work. For the amg model (srt) they make a kit that overdrives the supercharger (more boost) and underdrives the rest (less resistance). The kit is about $1,800 and will put 30 hp more to the wheels. I talked to the guy there and they also offer an ECU reprogram that will add about another 20 hp AFTER the pulley kit.