If you fit a "newage" STI tmic, and a decent late series VF turbo will make for a very nice classic, VF34,35,43 or 48 with a decent exhaust system should see 320/330bhp nicely and keep some decent spool up very little lag etc.
I had an FMIC on my classic, but I did not suffer badly from lag, as others on here will tell you.. however it is good few hours of fitting and cutting your front bumper up to squeeze in.
The classic STI top mount is rather limited compared to the newage ones (newage ones good for circa 400bhp, classic ones a lot less)
As Steve says above they do fit, you need to "modify" a bracket or 2.
Fit some decent brakes you will be going a lot quicker
