I was going to order the 1.9L Z3 shifter and do the conversion like so many here have done. But, I was having trouble getting some of the parts from the dealer (including the shifting lever), so I decided to find another (simpler) alternative.
I ended up calling Ronald at Autosolutions. It was clear after a few minutes of talking to him that he's put considerable thought and engineering into the shifting mechanism and how to improve it.
I decided to order his short shift kit, which includes the shifting arm and all bushings needed as well. It's all CNC machined and very nice. I'll report back later once the car is back together.

Since I still have a lot of the pieces for the Z3 shifter upgrade, I may just get the rest of them and sell it together at a discount. If anyone's interested, PM me, but I think this solution is a much better design.