my friend has a 89 supra and wants to swap it for a 1jzgte engine. Is this crazy or could it work, and how much is it gonna cost...also he wants to use the car for drifting so hes gettn new coilovers sturts and undercar braces

Yes it is very possable, which you would have found out if you checked out the other sections, cause I just answered a bunch of 1jz posts exactly like this one. As for the bracing, tell your freind not to waste his time, the MKIII is 3600lbs because it was built with strength i mind. Drifing.. come on tell him to quit watching so much Initial D and try racing the right way, it takes twice as long to go around a corner sidways on a track as it does to do it right without squeling the tires, but to each there own I guess.

would this car be extremely fast with that engine

Not extremly fast by any means, but it does have 280ish stock, but it's all about the potential the engine has. So it has the potential to be extremly fast with the right upgrades and tuning.