Well, the Flowmaster 70 series II DeltaFlow is inatalled, mission acomplished. There is no inside cabin noise while cruising, and only mild noise upon accelleration. I went with 2" tubes, and the mechanic at the place where we have work done said the what I did will keep back enough pressure to keep the valves from getting burnt. 
The only down side is that the FM 70 does not come in stainless steel.
The only down side is that the FM 70 does not come in stainless steel. 
