We sold a few Motordyne systems in here, can get you the ART pipes. The Motordyne ART pipes are a bit more expensive than the Berk HFC for example and way more expensive than test pipes.
We prefer/supply SPL parts, you can try Clark Motorsport or Cougar Store for Whiteline.
http://www.350z-uk.com/topic/94574-torqen-370z-full-spl-range-best-suspension-upgrade-parts
Adrian
While awaiting Invidia to reply, I've listened to that video several times, sounds like normal rasp to me.
As for the leak, Nath says the garage that fitted the exhaust swapped the left with right pipes in the Y section. Has anyone else did the same with their Invidia exhausts?