IMHO, it's a waste of a perfectly good brushless motor on an airplane that doesn't need it.

If you would still like to give it a try, and please don't let my opinion deter you from trying, I would go with the 3.3:1 geared setup and the recommended 8x6 prop. The plane is much too draggy to take advantage of direct drive, and the tiny 4.7"x4.7" prop would barely stick out beyond the cowl!

Oh, almost forgot about the where to buy part... You can buy direct from AstroFlight at www.astroflight.com. You can buy from Tower Hobbies. You can buy from Hobby People. You can search the web for "AstroFlight Brushless motors."

By the way, the tiny Astro motors generally come with the speed control already pre-wired.