i need to replace my dual cats, is there really much performace difference between the factory replacements and the aftermarket hi-flow ones. and i mean more then like 2-3 hp difference since it does have 2 cats, i can understand if it had only had 1 cat there could be a bigger difference. the reason being is i need it done soon and not wait for shipping.

 

2-3 hp, you're correct. A little better sound from a high flo as well.

The only reason I'd suggest a high flo is for the fact they're usually much cheaper, however factory style ones usually clean much better.

 

Check prices from GM and, say, Summit, and your choice will be easy.

JamesC

 

yea I about fell over when I called the Gm dealer for the dual cat pipe assy and got a price!

 

Yeah, your going to be better off getting high flow cats. Your looking at about 100 to 200 for a good set. Compare that to the factory......350 to 400 each! The plus side to it, besides being cheaper, is that your exhaust will be ready for any upgrades you do to motor.

Another option you could do if your emissions are not super strict is you could take your old ones, hollow them out, push a pipe through them and then weld the shell to the pipe. I've had mine this way for over 4 years, passed everysingle time with flying colors. That is both the sniffer and visual.

 

after looking a factory prices, i went ahead and order some off ebay. 2 magnaflow cats #94015 including shipping came to $94, so i got the best of both worlds, better cats and hella of alot cheaper. thanks guys

 

well just so you know, they probably don't clean the emissions any better (probably worse), but they should still pass smog and they'll flow/sound better.

Another happy person, saved from getting butt raped by GM stock cat prices

 

I dont know why you guys think aftermarket cats would do their job worse than factory cats. Aftermarket companies have to submit their designs to CARB to get an EO number, and if they dont meet the same emissions standards as factory, they dont pass the test. My car passes cleaner than stock with dual 2.5" Magnaflow cats on it, so they do work, and work great. Factory cats, especially in the thirdgen era, were designed to make the engine pass emissions, regardless of their effect on power.

 

i have no idea if they were better on emissions or not, but being better flowing and cheaper, i aint complaining