iv been doin alot alot of reserch on pipes hear are some good ones trinity been makein good quality pipes 4 over 20 years DMC afterburner comp (a honda pipe), motoworks slip is better then thier own full system so not motoworks, drd is a lil better with yamaha but still good ,dasa,a really good one fat boy 4,curtis sparks is defetly up their, LRD was horse power king on a suzuki 450 dont know bout honda. look some of those up those are most of the top best