This is funny, i comes up every few months. Trust me, you don't know half the work it is going to take to accomplish this. I have a 90 sentra wagon rear in my KN13 Pulsar chassis. The rear diff is the same as the GTi-R SR20DET trans I used. It was actually pretty simple on the front to get the GTi-R axles, hubs, trans and all that installed in the pulsar. 3 custom motor mounts and a custom dog bone mount up front did that. The rear is completely weld in. Many of the suspension points and stuff on the AWD sentra wagon are part of the chassis and not bolted on. The fuel cell will have to go in the hatch with a custom unit, not other way to do that. Also, you won't be able to slam the car if you want exhaust, I have a custom side exit on my car due to lack of exhaust channel. OR, you can do a ton of body work and widen the center channel of the car.
Brent