The only thing I see different between the single and dual cai's is the looks. The dual definitely catches everyone's eye. Powerwise, they appear to be similar. My home made single has helped my car perform just the way I want it to. I also have the C3 SC pulley, which is equivalent to Eurocharged's new 65mm one, and their tune. I also removed my rear cats and resonator for that little more growl I wanted. Someday I may get a larger HE, but the car is running great without one. Oh, and great choice on the Michelin Pilot SS's. I've read really great things about them. Good luck and you'll love the added power for sure!