the noise has never bothered me, ive got a few friends with all straight. when i had my chev with the 6.5 td i just had the 3.5" down pipe to a 5" pipe that cut out infront of the rear wheel. interior drone wasnt that bad, but it was loud eneought to set off car alarm:rofl
but now i am quiet to the world with the TDI, even thou i dont have a muffler