I'm trying to get the best cat for all around performance. I have a cat back and down pipe. I will be intalling an Apexi Power PC before I install the cat. I just see so many different ones on the market. I want it to be as light and as less restrictive as possible.

 

Are you still using the airpump? Because if you are, you need to make sure your high-flow cat is fully plumbed for it. I have a Petitt that I haven't put on yet because there is just a little bung on the cat, and the only way I can see to make it work would be to weld the fitting from an existing cat onto it, and I don't want to totally trash my stock cat...those things are $2200 bucks if you have to buy them new!

 

If this is your main concern I would go with a good quality metal substrate cat. SMB makes a good direct fit cat with or with out the airpump bung. Search on the forum for them.

 

I bought a 3 inch magnaflow for 119.00 and had a mufflershop weld a pipe and flanges on it. I use the airpump with it. I weighed it and its only 6 lbs. The car runs and sounds great with the dp, magnaflow, and rb dual tip.

 

Go the 3rd Gen parts section and ask for the section of tubing that leads across the transmission to the airpump. There is a section that is bolted together with a gasket just like the stock piece close to the main cat. Use the piece with the studs on it and have that welded to the bung on the hi-flow. Not sure how the Pettit unit is, but my N-Tech cat had a small piece of tubing with a 90-degree bend already welded to it, so all I had to do was cut a small straight section with the attachment and weld it on. The stock fitting coming over the transmission fit up perfectly, and it's attached to rubber tubing anyway, so you have some maneuvering room. I'm sure you can have something fabricated using the tubing section I've described. Hope that helps.

 

The Bonez cat is a good long lasting hi-flo cat. The metallic substrate cats are around, but unless you want to be experiemental, just stick with the Bonez.

We don't have enough data yet on the longevity of the metallic substrates on the RX-7 yet. However, some of the RX-8 guys are seeing some of those failing a little premature.