RE: Q500 entry-level Q's
Vipers are the way to go with the airplane - a few simple mods and they are reliable and fly very well. As for the motor - I would recommend that it is inexpensive, available to all, bereliable and use a single prop. Most here in the states use theThunder Power Pro-40 with an APC 9x6 thougha fewgroups do use TT46's or OS46. Some of the engines on your list are no longer available new - I would stay away from anything not available new to everyone.In the airvipers with a TT Pro-40 are all remarkablysimilar in speed regargless of whatthey maytack on thegroundwhich places apremiumon pilot skill and practice as it should be. Best of luck!
dan