Has anyone tried these on a NA engine? I've been looking for ways to get a faster 6speed and a lot of posts go unanswered besides saying get an srt. I still haven't found anyone who has bought a new cam or swapped the 3.7 block besides renntech. Sooo I think we need to start experimenting instead of condemning our 6 speeds by saying they're weak. There is a company who makes clutch kits for the slk320 and crossfire they're just vague in the descriptions.