Originally Posted by Ape Factory

They are indeed. Stillen did a brief on it and referenced the compressor maps showing how upping the boost gets them well out of their efficiency range. All the gains are going to come from other efficiencies aka exhaust. And not everyone can run test pipes, nor should they. So you have that option and tuning. I know there are some Silver S models (SS for short!) which had decent gains with bolt on mods and a tune but a cat-back exhaust, by itself, is netting around 15hp. It's almost the same as the current platform. Little gains for big bucks.

I predict most Red Sports (RS) will maybe see around 440whp with all the bolt-ons and a tune. Not bad but I think 500hp is out of the question (safely).

Link:
https://blog.stillen.com/2016/12/to-...30ddtt-turbos/

Edit: The new Z is at least two years away so I wouldn't suggest things one way or another as they could change or "upgrade" the turbos between now and then. I think it's unlikely, given Nissan's snail pace for evolution and propensity to reuse old parts, they'll be any different than what's on the Infinitis. The SS turbos are the same as the RS but the RS has an optical sensor allowing the turbo to be spun faster and closer to it's limit.