Since you have the RIPP posted I assume you are looking for one the moves the muffler to under the passenger compartment? I like my Pypes HGC system, although at lower highway speeds the drone is pretty loud. Acceleration seems improved and fuel mileage is up by 1 mpg around town. Not much difference in mileage on the highway. I am interested to hear RIPP's system, they claim to have a great sound when you get on it.