SSW, Here are some pics to look at.

There is a pic with a G-26 w/ bisson inv. wrap on a G.P. P-6E. If you look close enough you can see where I had to cut out the cowl to clear the muffler.

I also have a shot with a G-26 w/ a G-23 muffler modified on my DR-1 to show the pipe going straight down.

And a few shots of the beaver with a G-26 installed with cowl on and with the piping out the right side of the plane. I haven't soldered it up yet but you can get the idea. I don't yet know if the silver solder will hold up against the exhaust temp so it may have to be brazed together. You can also see the G-23 muffler was modified slighty by a hammer to clear the cowl.

The copper adds about 3-1/4 oz.s of wieght. Again this is an experimental idea.

If noise restriction is not a problem, B&B does have a G-23/26 header pipe that also could be used.

I wish they made 1/2" 90 and 45 degree elbows in aluminum like the copper fittings. One could really go to town making light wieght custom exhaust systems. Coming up with a exhaust system that fits in cowl always seems to be a problem.