Read the thread on Saitos and their "ugly" mufflers. I have been running my Saito 72 w/out the muffler for one season now and have not had any problems. Does anyone else do this with their 4C? It is a little louder (but sounds good on my P-51), can hardly see the header pipe where it exits the cowl (looks great this way). Will this cause any long term problems with the engine? On a side note, this thing runs like a top this way, very low idle speed and runs very smooth on the high end. No need for the pressure line to the gas tank, it seems to draw fuel fine without it.