Best catalytic converter recommendations

[KShortell]

Well, the time has finally come. The catalytic converter on my stock '86 350 has finally started to do the "death rattle". It was blowing out the white ceramic pellets a couple of years back, but still passes emissions. Now that I've had the valve stem seals replaced, a new cat has a better chance of doing a good job anyway. I think that the "pro" I had do it didn't do the valve cover gaskests right, though-- the side of my block and oil filter is covered in oil...

It's started to idle lower, roughly, and kinda funny the last few days and the cat has begun to rattle-- the same rattle the cat in the Jeep had when it went bad a couple of years ago. At least that one was still under warranty. SO, I'm pretty certain I need a new one.

My question is which catalytic converter have y'all had the best luck with? GM, Random Technologies, Catco, etc.? I'm ideally looking for something that will just bolt up and not require new pipes due to a different length.

My exhaust is the standard Y-pipe, 2.5" exhaust, AIR at the manifolds, and single stage (no air injection) catalytic converter. This 2.5" dumps into a Flowmaster 3-chamber Delta Flow with dual 2" outlets.

Thanks for the input!

Kevin