i gutted the stocker on my son's 90. if you can weld i think you can get the same performance for 10 bucks. there are three tubes that are louvered. the outlet is very restrictive. first cut off the heat shield, save the bands. you will need to weld them back. next open the housing, use a die cutter. every place you see a spot weld is a gusset inside. leave the gussets. you will have three pieces out if the top of the resonator. rip out all the tubes and replace the tops. next go to the outlet and remove it, but save the ball. cut in a hole for a three inch pipe. weld in a short piece of three inch, next section off a piece of the ball the same size as the three inch pipe, weld the ball to the pipe. you can section off the other end of the ball, but only to two and seven eights inch in dia. or it will not fit in the socket. just measure very carefully, or the length may not be the same.