The simplest choice is to replace the shifter with a Z3 1.9 shift lever. It will reduce the throw by about 33%, which I found to be a nice choice. It requires the shift lever, bushing, a couple of retaining clips and washers.
http://www.realoem.com/bmw/showparts...13&hg=25&fg=05 You will need parts 5, 7, (2) 10, (2) 11 you may wat to get a extra #11 just in case it takes flight (better to have and not need, than to need and not have). You will not need the yellow washers #10 for the shift lever end as the bottom is slightly wider than the stock one. The 1.9 lever does not require any modfication to the selector rod as do the Z3 M shift levers, but the throw will not be as short as the M lever but still nicer than the stock lever. BMA Auto Parts sells the complete kit
http://www.bmaparts.com/epcgetspecia...34%2FE36%2FE24 Good luck and enjoy