I am in the middle of finishing up a modeltech extra 300 arf. Putting an O.S. .25fx into it. I am trying to figure out what kind of muffler to use for it. I know from reading posts here that many people have this plane and engine combo... my biggest question here is exactly how to cut up the cowl for the stock muffler. The muffler will almost fit completely in the cowl. Can people post up some picks of what they did with their cowl?

I thought of cutting a 1" wide by 3-4" long slot for the muffler at the bottom of the cowl... but that doesn't look all that great. Also tried looking for a Pitts style muffler for it, but can't find one for the .25fx, only the .fp. Mac's makes a muffler that would fit, looks much slimmer designed, but lots longer too, I'm sure it would fit up in the cowl, though I am not sure how the end would come out... don't wanna spend 30 bucks to maybe decide it won't work.

any ideas, pics, suggestions?