You need to go over to
www.fiero.nl and do a search for turbo 4.9, or just send PMs to
PBJ and
Her86GT (that's the car that does 12.2, there's video to prove it). Their build thread can be found here:
http://www.fiero.nl/forum/Forum1/HTML/023354.html so that might interest you, it includes timeslips, but I cannot find where the videos are (they're sick). The fastest Cadero (Cadillac + Fiero = You get the picture) was made by
Master Tuner Akimoto at least that's the claim, 11.97 on a highly tuned 4.9L, He also has a Turbo'd N* (one of about 2 actually functioning out there),
PBJ is currently in the midst of a N* TT, though I havnen't seen any updates in a long time.
Enjoy the reading, I know I did!