I just had my Cats replaced from stock to Dynomax, because my factory Cats started to make noise. After 120K it was time.
My question is such;
What good are Headers on a dual cat TPI(or any 3rdGen) if the Cat(s) are original?
I mean, besides streightening the exhaust pulses from the heads, the gases still encounter the restrictive and in most cases(like mine)clogged , due to high millege, catalitics?
I, now have a complete after market exhauast, from end to back.
It "feels" great but I'm yet to check out the benefits at E-Town.
Like I said before, if you got HEADERS and a CATBACK but stock CATs, are you getting better exhaust flow?
Isn't your exhaust only as free flowing as your LEAST restrictive part?
Any conflicting opinions are much welcome.
Mike

 

The dual cat setup was the least restrictive cat system the factory ever used on 3rd gens. It's possible for the factory dual cats to outflow a single 3" aftermarket. With dual high-flow aftermarket 2-1/4's, you're doing even better.

Single cat is simpliest, no doubt. My fellow 3rd gen bud still keeps trying to convince me to "convert" to duals, though.