Will a 2.8L V6 bolt into a 4cyl '89 Trooper (manual trans)? Or would it require modification? Better yet, would either the 3.2 or 3.5 V6 bolt in? Thanks.

Yes the 2.8 will fit fine without mounting modifications but there are a few wires that you will have to extend. to make fit. the others will need the monts moved further forward for it to fit.

the answer is no, idiot.

I believe that the transmissions are different but the motor mounts are the same. I recommend the 3.2 s engine code from a camaro or firebird 93-95