My street bikes have Thunderheaders on them, but neither bike is stock. the only 2 race bikes i now own (a 2004 RM250 Factory Super-cross, and a old top fuel bike built in 1985 with 100ci Shovelhead direct drive with slipper clutch running 60%pop, ) have handmade pipes on them. Like I said earlier go for the look that suites you and put a good tune in it and ride it till the wheels fall off. One of my ridding buddies has a 2005 night-train with Rinehart 2-1 pipe on it that sounds awesome and looks great. Pipe, SERT and SE intake - everything else stock, bike makes an honest 76hp and 85lbtq. after being tuned.