I've seen the aftermarket kit installed on a coupe. If was actually a good quality Phillips kit. efore I popped the hood to work on hte guys car I actually thought they were the cheap eurolights by ractive. The light is not spread very nicely because they were meant to be halogan lamps, not HID/Zenon. The projector Z kit actually has you open up the lamp and change the light refraction inside the lamp. This would help, but I can't comment on how much. I haven't seen them.
1997 Z3 with N/A power adders....