dr. gonzo

ive been all through an mx3, built it perfect and no troubles there. once i did this, mazda amazes me. i love it. so i immediatly find an rx7 and goin compltely by feeel on this one, i have no experience with these cars. but i bought one anyways, cause im gonna learn damnt, these things are way to sexy to pass up on. so i found an 86 gxl that is smooth as hell, runs like a champ. can i put everything from the motor, tranny,driveshaft. and rear end in an 89gtu i just got with everything perfect but the drivetrain/motor. will any of these parts bolt in here if not all, and what would be involved. i know its an s4 motor into an s5 body but if i changed everthing would it work without any mods? also what would i need to do to lighten this setup upon completion? i would like it to get atlest to around 2200lbs or least possible