congratulations on owning a supra
www.cygnusx1.net/supra is the online 1990+ repair manual
there's a thread in the faq section on modifying which will help ya out
but usually first things (i know you have a few of these already)
intake
exhaust
boost controller
intercooler
intercooler hardpipes
upgraded ct26 (stock turbo but with upgraded compressor wheel)
lexus afm
550cc injectors
more boost
(by this time you should be fairly flying
)
and if it hasn't been done already... do your headgasket heh