I mentioned earlier about difficulties with the STI flywheel & pressure plate. I went and got a whole new WRX setup to use on the car instead but took some shots side by side while I had all the parts.
Right side: STI Aasco 11.5 lb aluminum flywheel, Exedy 15803 stage 1 clutch and pressure plate
Left side: WRX ACT 9.5 lb chromoly flywheel, Exedy 15802 stage 1 clutch and pressure plate
Basically the WRX parts are the ones you should be using with the 5sp. Your life will be a lot easier if you do. For a street bug using this swap I'd go with a heavier 12-15lb. flywheel, but in the race bug lighter is better. The WRX stuff is a bit smaller in diameter, which reminds me of the bug vs bus flywheel/clutch/pressure plate questions when running my old type 4 motor.