Is there anything I can do to see if the clutch is slipping? When am in 4th 5th 6th gear when the revs are low and I floor it the revs go up to about 4k but the car doesnt go as if its turbo lag but the revs go back down and the car pulls.It doesnt do this in the lower gears.The car has done...

Im losing sleep over this...and need some advice ;) Currently own an M3 CSL which I've had for 2 year. Its been used properly, 2 ring trips and roughly 4-5 uk track days. Before the CSL I owned an .R (No.20, if its out there?) and I cant get rid of the itch for another. A big part of me thinks...