ARK exhaust is just another knock off! Any one that buys knock offs ends up hating life because of the thin wall stainless and very poor welds! If you can find the authentic HKS for $700 on Facebook jump on this deal. It's not too loud and the construction is excellent, they've resolved all their issues not to mention since moving back to Japan the cost has increased 30%!
Gary

 

There's a good quality option made by Magnaflow for G35 with moderate sound level
http://www.carid.com/2004-infiniti-g...-20209933.html
(there's also a sound clip on our website)
Has anyone seen it in person?