well i figure, this is how the exhaust is setup on the R32, with the flapper opening a hole after the last muffler...

in essence, opening that blanked-off hole in the muffler would increase the exhaust outlet by 50% of its current size. hell, you could even put a flap on that outlet if you were really keen

also seems like it would be easily reversible if you didn't like the sound.

i might go see an exhaust shop this week, but was hoping that someone here might have already done this so as to give an idea of how it sounds in real life.