How much more noise would this item make to my 94 WRX, baring in mind I already have a 3.5" down cat back, and straight a through centre Cat. So this item will obviously eliminate both CATS.

http://cgi.ebay.co.uk/SUBARU-IMPREZA...QQcmdZViewItem

I'm also after a very chattery dump valve if you know what I mean, any ideas on a good chatter?


Thanks, I appreciate it.