I will be working on mine some more this next weekend I think. I will take some pics. As far as prop right now I have a 15-8 APC have also tried a 16-10 MA Classic but just didn't pull the R's that I wanted. Next I want to try a Graupner 15-8 3 blade.
I have made many of my own exhaust out of thin walled steel tubing. I usually start out with a 1" square tube that gets bolted to the head with 1/2" down tubes. On this one I used a 5/8" single down tube. I just braze them together and of course cap and braze the ends closed. I would love to TIG them using aluminum but don't have access to one so I use steel but they really are not that heavy since I use thin wall. Of course not everyone has access to a torch either but is usually easier to come by. I find that most mufflers just don't fit without severe cutting of the cowl so I make my own.

Randy