im cheap, do the muffler tips (universal) do anything bad to the gas mileage or back pressure of the engine?

If it does, the difference is gonna be so minimal that its not even worth consideration. I'd be more worried about sounding like Uncle Ben's Moped.

if it is just a tip and not a muffler then there will be no change in anything. changing the uffler only changes the sound.

alright, im probably not gonna do it anyways

If you change the tip to one that necks down to the size of a Slurpee straw..........sure.........that'll affect your engine performance..........in a negative way.

Actually.......it would probably just blast your tip off.

KiL