It's a Magnaflow from ebay. My setup is a 400+whp in an EF (90 hatch) , I have a fuel cell so my exhaust just goes straight down the middle and a little 45 degree bend out to the muffler. No other bends at all. I am going with a 3" exhaust and I was wondering if this muffler will suffice?

http://cgi.ebay.com/ebaymotors...ZWDVW

Theres different body lengths such as 18", 30", etc. What would the difference be? Thanks