My cats are going bad or have gone bad. Annoying rattling, check engine light on due to the car running lean. so my questions are...

brand recommendations?
does it really matter as far as "high performance" cats?
how much power am i losing with bad cats due to the air not releasing as supposed?

I bought the car with an aftermarket exhaust. I dont even know what kind but im pretty sure its just an axle back, so would it be better to just get new cats or go ahead and go for a catback system of which brand i know? both of which i cant afford right now, lol. Thanks

 

Are you sure you are on OEM cats? I've heard of some other aftermarket cats breaking down prematurely.

 

No, im not sure. I just saw in the raspy exhaust thread about the berk cats messing up....I had a leak in my y-pipe so i took it to a custom exhaust shop a few months ago (which they just welded) and asked about the rattling. they said it was the cats needing replacement, but i dont know anything about the exhaust. i tried looking around the mufflers for a logo but was unsuccessful.