I used this flywheel:
Audi V8 4.2 8 Bolt to O1E/O1A Gearbox | TTV Racing Component Manufacturers
with an Audi S4 B5 clutch friction & Pressure plate. Works on a 986 5 speed and 987 5 & 6 speed boxes.
I had to drill the transmission for the manual crank position sensor and use spacers to get it the correct depth in the bellhousing.
Everything bolted up easily in the end and works great. I like that i'm not using Porsche clutch consumables - much easier on the wallet.