The proper muffler if other than stock is very important to help control CIS and rasp. The UQ does a awesome job killing the drone and rasp but the bottle resonators (Bpipe) will completely eliminate it and leave you with a clean exhaust note. There will still be a slight bit of rasp/CIS with the UQ alone so yes I do recommend catted or resonated catless bpipes as well. The sound clips of my Titan on my website are with catless resonated bpipes. Cajun Bpipes | shreveport, LA 71129