Is there an exhaust that would allow this?
 

I was wondering if there is an exhaust that would allow a 370z to have a functional rear diffuser?
The closest I can think of is in the picture below. Another one would be a side exit exhaust like on the jun 350z but there isn't one for a 370z.

Exhaust can be made to fit anything... finding a functional rear diffuser is the key here. even with that yellow jun 350z i believe they still had the exit ports for the exhaust. and the 370z... they just bondo/painted the exit ports. but as far as exhaust everything would have to be custom fabbed.

I think they just vinyl-wrapped the exhaust holes in the diffuser.

Functional rear diffusers aren't going to be simple no matter what. It will have to be at least a few feet long on the underside of the car, and it will have to close off its own front edge, so yeah there's going to be compatibility issues with just about any aftermarket exhaust. If anything the factory rear exhaust section is probably one of the simpler ones to fit a diffuser over.

I wonder how hard it would be for someone to fabricate a complete undercover for our car? Replace the stock front undercover and make a relatively smooth underside all the way to the rear. At least then you don't have to close up the rear diffuser in the middle of the car (over the exhaust and driveshaft area). A universal full-length undercover with some diffuser fins in the rear could be custom cut for various aftermarket exhausts to fit through it.

Probably be hideously expensive and not sell many units though :(

ive been waiting for a nice rear diffuser for a while now.... not many options out there.