[Don]

Paul, taking into consideration that loss of HP/performance was accepted in order to have quieter pipes:

Used 3 1/2 " round exhaust tubing, reducers at both ends to go from the 3 1/2 " to 3 ", filled the joints. The modified reverse flow muffler was placed inside the tubing with ends to act as a seal as I wanted to maintain the stock appearance of the side pipes. 3 1/2 " tubing is as long as possible to still be able to attach the turnout

Attached the front to the header extension/connection and the rear to a turn out, all joints were filled. Looks like conventional side pipes, used the same mounting hardware.

The cones mentioned by Garry are in the front. The motorcycle baffle was placed internally after the muffler. Reduced the dB , but do not have a measurement. For normal street only driving, never noticed the reduced HP. Will satisfy the dB reduction needed for use within a " retirement "community

Summit sells the tubing, reducers and turnouts

A consideration when pointing the turnouts down depending upon conditions is the " possibility " of blowing dirt and other debris onto adjacent cars, in the pits, on the street etc.