SierraD.,
The motor is mounted at 90 degrees. I use a bisson pitts style muffler. The only prop I have ever had on it is a master airscrew classic 18x6. It pulls it with plenty of umph!!. The only thing I changed from the stock set-up was the tires. The stock ones are like hard doughnuts. Plus they wear out rather quickly on pavement and look like crap as the white foam they are made of statrs to show. I put a set of inflatable dubros on it. They look great and even help out a great deal with bunny hop down the runway that "some" people have once in awhile. Hope this helps.
Stangevil29