ok this Model Report business.
you cant import 97 Turbos - nothing to do with transmission. Fails on emissions on the Turbo models. The NAs just about make it. Emissions regs get tighter as the years go by. If you did manage to scrape through on emissions, it'll only be applicable to 97 - 99 (or sommit), cos the regs get tougher thereafter.
I've been through all this (believe me - I had a 98 VVTi stuck at port for about 7 months, even considered tunneling!) ... and there aint no loopholes anymore - only favours.
o and cost - if you get through first time you're looking at about £3500 - if you fail, then there aint no rebate. You would own the rights to the report and others would pay, say £250 to use it, to get their Supra through ESVA - then you can register it for UK roads.