Originally Posted by djpathfinder

I have ERZ HFCs on mine. HFCs reduce the restriction of flow of exhaust gases as there is less packing material compared to catalytic converters. This has the effect of improving HP (somewhere around 12-15 HP or so - HFCs in general), complimenting the flow rates of a cat back exhaust, as well as deepening and making the exhaust note a little louder.

There is a chance of getting a check engine light (CEL) when you replace your cats with HFCs (even more with test pipes), but not everyone is noticing that. If you are getting a CEL because of the O2 sensors on your HFCs, stuffing steel wool in front of the O2 sensor is a documented fix. There is a lot of information about HFCs on this forum.

One thing I have to add, the caps for the O2 bungs are only hand tightened when they leave the factory, so make sure those are properly tightened when installed on your car, otherwise you'll get a nasty rattle as the caps unscrew themselves loose from vibration.

This is a good price for a quality piece, and good mod to your vehicle...GLWS, OP!