Hmmm... interesting. I thought I'd read that, even though EP uses 100-cell cats, the surface area of the cats is sufficiently-equivalent to the stock exhaust's cats as to not cause a CEL even without a tune.

Curious... hope to hear some additional expert-opinions on the subject.

HI,Its a very good exhaust ,expensive side but great quality,their are other options if you want power and to be quiet.....I have a Milltek 100 cell system that is very good also and I am very happy...It use to be one of the best for power before they came out with X-pipes,,,as I have been told before...Do your research...Good Luck

Im in the process of trying an AWE exhaust. AWE claims NO DRONE at all. The old fabspeed with the tipronic transmission was not working for me. I would like to dyno the car after the AWE exhaust to see how much power i have actually lost with it.

HHmmm. Something does not sound right here... EP is super high quality and I have not seen one of their exhaust systems throw a cel for bad cats.. They are sponsors here and you should PM them about it.

I installed mine 3weeks ago per their instructions. No CEL.

Got the car back today. Europipe exhaust and BMC filter. Just had the ecu tuned by sport tec. It's awesome. It feels like a completely different/ better car. What about diverter valves? Suggestions? Thanks.