bzr16v - I think you would be hard pressed to get the sc14 in an ae92, as they sit out a lot further from the block than the sc12 and would be very close to, if not hitting the firewall. I havent actually measured this up so i could be wrong but i'm pretty sure it wouldn't fit.
Gremlin - Dont know what sort of boost you would get with the biggest pulley, but i think a reasonable estimate would be approx 16-17psi. I'm planning of fitting a 175mm crank pulley to mine soon when i put my new computer in. ATM it runs 11-12psi (with no intercooler and very short piping it actually ran 13) so i'm expecting around 15-16psi spinning it at around the same speed as the standard sc12.(the sc14 pulley is larger.)
The sc14 is the biggest s/c Toyota made that could be fitted, but if you wanted to go aftermarket the sky (or budget ) is the limit. I have seen an Eaton s/c fitted (but i dont what size it was or boost) and it was reportedly running 240-260bhp. But personally i wouldnt want to go too much bigger than the sc14.