Want to swap out Cats to high flow. what size?

My cats are stock and have 110K miles on them. I'd like to swap them out for high-flow metal matrix cats. I've heard various sizes but im' not sure what mine are:

Application: 97 coupe (stock manifolds)

thanks in advance

[c4c5specialist]

HI there,
Keep them and dont change them.
Fact is, yes aftermarkets flow more air, but they will set DTC in the PCM and your service engine soon light on.
The 97s without the precats were better then the newer onces with the precats.
Allthebest, c4c5

I was told that I could tune out the rear O2 sensors so this won't happen. The main reason i wanted to swap other than age was that a dyno tune I had in April of 07 was causing me to run rich. Doesn't that ruin the cats?

[c4c5specialist]

HI there,
If you are modifying your vehicle to that extent, it would be prudent to simply install long tube headers.
Tuning is only effective, for the LONG TERM RELIABILITY, if you have at least headers.
Any converters in the aftermarket will work and NONE have proven gains over others.
Allthebest, c4c5

I recently installed LG Street series long tubes on my '03 z06. With these headers, high flow metal matrix cats 3" inlet 2-1/2" outlet stock diameter to an x pipe. The dyno showed 374.9 rear wheel horsepower. Everything else is stock including the air cleaner and element.