Dave, sound like you need a catback system, if you want to try and maintain an OEM like sound, they we have the Milltek system which would fit the bill, if you wanted a bit more noise then the Cobra resonated cat back system would fit the bill perfect, you can see this system here - http://www.350z-uk.com/topic/63096-cobra-sports-exhaust-from-cougar-store/
The Milltek system can be seen here - http://www.350z-uk.com/topic/56130-milltek-exhaust-system-from-cougar-store-350z/
More systems here - http://cougarstore.co.uk/index.php?main_page=index&cPath=1_10
Drop us a call or PM us for more info...