Just put a set of V&H slip ons on my 06 RKC. It's fuel injected, so your milage may vary. Put the muffs on last nite, ran it today for about 70 miles. No popping on decel, seems to run great so far. I will get a remap when I put on the SE A/C, but with just the slip ons it's running nice. Hope this helps.