I went through 2 catco cats in about 8,000 miles and the third broke 2 days after I got it. I had to go through all of the diagnostics to make sure I wasn't running rich, etc... It turned out the bonding agent on the catco's just melted away and the core started rattling horribly, seeing the bonding agent blow out my muffler was not cool... We thought it was just a bad batch of cats, but 3 in 8k miles is ridiculous...so now I have a magnaflow and it works very well.
You won't get any HP gains like that on your set-up. The oem cat is superb, but pricey. I bought a Davico cat a few years ago to replace my cat on my old '91 NX2000 from www.Stranoparts.com. the price was great and the installation was great. It was a direct bolt-on.
The modded to moderately modded SR20DE NA does not gain much in the area of HP from a straight through test-pipe or high flow cat. You have to be pushing some serious air (HP) to have a Random Tech be worth it.