Here's a thread from e46fanatics
http://forum.e46fanatics.com/showthread.php?t=206363&highlight=clutch+stop+install
Here's how Rogue Engineering markets their Clutch Stop.
http://www.bimmerworld.com/html/rog...clutch-stop.htm
"Limit clutch pedal travel for faster shifting
Rogue Engineering Clutch Stop The clutch pedals in manual transmission cars often have way to much travel past the clutch engagement point. This additional travel adds additional time to your shift, slowing your acceleration. Designed to stop clutch travel immediately past the engagement point for faster, more precise shifts.
Fits all E28, E30, E36, E39, E46, Z3, and Z8 cars with manual transmissions. (NOTE: some later E36 and all E46 BMWs require the clutch to be partially or fully depressed in order to start the vehicle. Because of the nature of the clutch stop, it does not allow the clutch to be depressed fully, to the floor, and may not activate the switch to allow the car to start.) "