I recommend Ron Stygar's Adjustable Clutch Stop to anyone with back or left leg pain. Reducing the length of clutch pedal travel has already made a real difference in my sciatic nerve inflammation, in just two days of major stop 'n go commuting! Ron sells these easy modifications for $25.20 (much cheaper than physical therapy) or shows you how to assemble one yourself on his web site (www.unofficialbmw.com).
I am not affiliated with Ron in any way, except as a very satisfied customer. He was very pleasant to communicate with via email ([email protected]). His clutch stop was also recommended on MZ3.net near the bottom of an article about his short shifters(www.mz3.net/articles/027.html) as adding speed and fun to the shifting process. Thanks, Ron!