Can I put a 91 turbo caliper into the N/A model? Will the stock rotors work with it or will have to replace it too?

Thanks

The caliper will fit.
I *think* the rotors are the same.
The only difference is the turbo caliper is 2 piston VS the NAs one piston.

you sould have no probles doing that, but you should consider getting all-trac celica rotors and getting them crossed drilled, with some 240sx calipers, I think you need the 93 generation calipers. check out racingstrong.org the guys a genius when it comes to performance