As others had responded to your other thread, no you cannot go to 17in wheels, won't clear your front brake calipers. And, from a recent thread, I see you've already replaced OEM 19's Bridgestone tires with DW's. Your remaining options are a combination of below:
- replace your current brake setup with Base's smaller calipers and rotors (and maybe the brake master cylinder as well not sure). I *think* you can fit 17 inch wheels then.
- keep your current brake setup, buy Base's 18 inch wheels and put fresh DW's on
- pay a good audio shop (or if you can DIY), lay sound deadening mat throughout your interior space. Trunk space and rear wheel well at least, as that area has literally no sound insulation. Go to the Audio sub-forum for more expertise on this.
The 17's on 350z is something like 225/50/17 and 235/50/17. The 370z 19's are 245/40/19, 275/35/19. The 370's tires are wider with shorter sidewalls, aka more contact patch to generate more noise, and less insulation. They are not comparable. You may be out of luck without spending some money