Best answer is it might. Back pressure in the muffler acts as a fuel pump to the tank. 4 strokes also use the back pressure to help them run their best. Another consideration is noise. You said it's quiet, but if you fly anywhere near a house this may be just enough excuse for someone to complain. Just don't mess it up for everyone else by causing a problem that wouldn't have happened if you just left the muffler intact. Not everyone has the same passion for flying as we do. They look at it as an intrusion and any excuse to whine - they will take it.

My 2 cents.
Mike