Hello everyone. I just replaced my stock exhaust with downpipes + catless system from JHM(along with the 91 octane JHM tune). It is as good as everyone said it would be, highly recommended!!! I have the full stock exhaust system including cats+downpipes. It is off a 2004 S4 with 75,000 miles and is in excellent working condition. Does anyone have a clue what I should ask for as a price when I sell the stock system????? Any input would be appreciated and thanks for the great advice regarding upgrades........