[drft92]

Primary cats are 400cell, most aftermarket manufacturers are offering 200cell cats. Ihave Fabspeed 200cell cats, they made a huge diffrence over stock(enough that my butt dyno could register the extra hp) as for odor I have yet to smell any unwanted sents. Now I cannot tell you how much db increase you will have from cats alone, I did a full setup all at once and I can say my car is very loud. I'm sure other members can chime in with more detail on sound. As for your choice in exhaust Akrapovic well you cannot go wrong with their exhaust system. GL man