My brother has a 7mgte on a Na 5spd tranny, when he got the car the clutch work for a while then it went so it was replaced with a new stock na clutch that slipped right away. now installed is a spec stage 3+ clutch he's been driving it for about 250 miles now normal. he told me it feels like it's slipping at 3500rpm, has any one had these problems with na tranny and turbo motor. any ideas, and what's the best clutch for this setup,