I'm about to buy a magnaflow cat for my DA but I'm not sure which size I should buy. I have a OBX header which has a 2" collector on it but my catback piping is 2.5". So would I want to get a 2" cat or a 2.5" cat?

 

you need the cat with the 2inch collector nd a 2inch outlet

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by billabong &raquo;</TD></TR><TR><TD CLASS="quote">you need the cat with the 2inch collector nd a 2inch outlet </TD></TR></TABLE>

sounds like you need the direct fit for your DA. those 2.5" catbacks are usually crimped down to a 2" collector where it bolts up to the cat if they are designed for factory fit.

 

Don't waste your money...your exhaust is only as big as the smallest part. You may just want to build a true 2.25" header-back system.