This is the way I look at it... If you are going to buy an mk3 turbo supra... The 7MGTE is included in that price for free. If you want a 1j, you are going to spend at least another 1000 on the motor, then at least a few more hundred on the install above that. For that money, you have a motor that could have had the shit kicked out of it for the last 15 years. Instead of investing 1500 into a 1j, you can rebuild the stock 7m to stock spec or above. At least then you know that rebuilt 7m is going to be a reliable motor.
Then... Since I am being awefully nice on the prices, the rest of that money can be placed into performance modification on the 7m. Yes you have more initial power with the 1j, but try to find replacement parts and price out some of the more rare aftermarket shit. Hold you jaw because it might hit the floor. Better or not, I firmly believe that you should stick with motors that were sold in the united states. At least then there is a surplus of stock and aftermarket parts.
Moral of the story... Is the 1J jdm tyte really worth all that extra time, money, and effort when you have a stock motor completely capable of producing shit loads of power? Treat her right and she will do the same for you.
p.s. Just a heads up... If you do plan on going 1j... i believe the 1j only fits the 90-92 crossmember so you will have to source one of those out if you get 86-89.
p.s.s.
WWW.7MPOWER.COM <----- GO THERE.