I know its not 350z but my japspeed S14 exhaust Turbo back incl Tubular Manifold didn't fit well it it used to hit on the underside of the car, But it was better than the POS Powerflow that had been Custom built by Stevie wonder previously,
But like most things in the aftermarket car world, You pay for quality, Ive had shitty ebay bargin bucket exhaust threw to the Titanium Fijitsubo i have now on all different sorts of cars and the difference in quality does increase with the £££ obviously there are some exceptions to the rule, Just depends on your personal standard on what quality your happy with.