Mike, the Milltek is well received, we've supplied and fitted a few, the non resonated system sounds super - http://www.350z-uk.com/topic/60927-milltek-370z-exhaust-system-from-cougar-store/
We do the buddy club but its a loud system, the Cobra non resonated system would make for a good balance priced at £395 and if you wanted to make it into a cat back system then you can add the Y pipe at £199...
You can see them here - http://cougarstore.co.uk/index.php?main_page=index&cPath=1_10
Drop us a call or PM if you need more info...
It's most likely broken between the mid pipe and rear silencer, common fail area for the OEM exhaust...
If you decide to replace it let us know and we'll be happy to help...