Our S3 was over revving between gear changes which as we all know, the most likely culprit is a faulty Clutch Switch. We bought a new one and it solved the problem. However, on taking apart the old Clutch Switch to try and find out what exactly goes wrong with them, we noticed a broken piece of plastic. The tiny piece had broken off a section which makes contact with the switch itself BUT and here's the interesting bit.... The way the switch works is quite clever as its fully self adjusting. Its actually the plunger part of the switch which is the self adjusting part when fully extended (the way it is out of the box). The plunger is on a ratchet type mechanism which slides down into the switch and your cars clutch pedal stops it at the correct position for the car. You can hear it ratchet as you push it in by hand. However, i think alot of peoples clutch switches may actually NOT be physically broken and instead just need resetting. If you remove the switch and fully extend the plunger, then refit it, it may actually stop the over-revving problem without the need to buy a new switch. I know they arent expensive but it would save you the hassle of having to buy one. We fitted our new one with the Clutch depressed as releasing the Clutch slides the plunger in, just to ensure we got the correct self-adjustment. Im not sure this made a massive difference but it was just a precaution rather than anything else. So, if your car is over revving between gear changes, it might be worth trying to adjust the switch yourself before buying a new one. If it works for anyone, let me know if my theory is right or not, it might save some people a bit of money.