recian

I recently bought a 86 model rx for a race car / project. In a local yard there's a 90 model turbo2 with everything still there but the hood and intercooler. I'm thinking of pulling the ECU, harness, injectors, manifold+turbo. I'm curious what else would need to be done, are just the rotors (compression) different between the 2 or is there a major engine difference? The car already has the bigger brakes and rear end.