had a major exhaust leak at the cat converter inlet junction for quite a while. i finally got around to fixing it and when i took it out for a test drive it is severely lacking power.

except for the noise it was running fine before i made the repair. The car has 350k miles and has the original cat. if i had to guess i'd say it sounds like a blocked cat. i'm going to loosen up the clamps and let it breath and see if that rectifies things. Any other thoughts? thoughts on aftermarket replacement cats? i hear they are only good good for a few years?

thanks!
\matt