so i cut out my stock cats, and installed the slp ones i bought on ebay. it definatly increased my exhaust tone and sound, and the performance is noticiable. highway kickdown acceleration is the most drastic increase, i'm very happy with the swap. i'd reccommend these to anyone wishing to increase exhaust flow.

 

Did they need to be replaced?? How many miles do you have?? How much did you pay for them, I saw $350 a pair on some website, also couldnt find any on e-bay. I have over 75,000 and I'm about to get headers and new exhaust and figured it might be a good idea to change them when I get the rest of the exhaust done. THANKS!!

 

they are technically cats for an SLP mustand x-pipe, i bought them on ebay, because they are slip fit 2.5". so who cares the application. Being that they're slip fit, my stock y pipe is metric... and a lil bigger than 2.5, but they butted up together perfect, and i just welded them in. i found them on ebay, from a company that used them once, for a dyno test, i paid 117 including shipping. SLP sells them for 200$. theyr'e the smallest catalytic converter i've ever seen, and they didn't throw an engine code....my truck only has 5000 miles on it, i hated my exhaust tone, and my cat's are huge. i'm told that some trucks like avalanche's and hd's have high flow cats on them from the factory... and i've heard those trucks, with aftermarket cat-backs, and mine was much quieter, so i found out why, and went one step further with these cats. definatly made a difference. sorry no dyno numbers or times for ya.

http://www.slponline.com/view_product.asp?P=M31040

 

just road tested it, in dry weather...... performance overall is greaty increased, very happy. out of the hole, it's much better even, which is weird, since i've decreased backpressure. much better hp per dollar than my catback.

 

What size and how much did you pay??

 

scroll up, all the info is in a previous post...... and a link.