are the frames the same with 86 and 88 gt's? or just front facias differant?

I'm not sure what you are calling the "frame". I believe the space frame that is under the plastic body is pretty much the same on all years. The 88 car has a different suspension then all the other years. the engine cradle is different on the 88 also. They wanted the car to handle better so the 88s got a Lotus designed suspension rather than parts off of a Cavalier or Citation.

Different "frame" front and rear -- want to put an 88 suspension on an early Fiero? No way, no how. We tried.

I read a link on Pennock's a few years ago that explained how to do it.