Just picked a used 08 YZ450 currently with a stock exhaust. Loud is ok on race days, but we have a couple practice tracks in the area that require DB Dawgs or Q4 or similar quiet pipes. Is there much difference between the Q4 and the Powercore 4.1 other than the noise? It is a pain to have to switch pipes back and forth for certain tracks. Lastly, worth the investment to go with the header "bomb"?