From reading the german BMW forums, the most popular E46 mod currently is to use the gearlever from the E9* "x" models (i.e. the 4wd ones). The part number is 25117553172. It goes straight into all 5 speed E46's and won't foul on the driveshaft - a lot of BMW levers will foul on the driveshaft, like the Z4 3.0 shifter.
25117553172 is a straight swap, gives a shorter shift without making the gears really heavy.
Some comparisons here (not the E9x lever above though):