I have had the CVEC Rear exhaust for the 2.5 Maxx. I would say there was a small increase in the bottom end, and much smoother transition through all the RPM's. The only problem I encountered with it was when I jumped. If I landed on my rear end, which I did a lot since I was new at this, the force from the pipe hitting the ground would get transfered to the engine. This would cause me to break engine mounts. I broke 2 of them in a 1 week period. I ended up ditching the CVEC pipe, getting a heavier duty engine mount, and putting the stock pipe back on.

If you want I will sell you my old one. It's not the prettiest pipe out there, but it seals fine, and structurally is in good condition. Let me know.....