Don't debate the merits of an air-cooled engine in a desert environment in the summer versus liquid cooled. Liquid cooled is your answer for sustained power under all conditions from puttin' around for hours on end to vast hill climbing. The cons are it will cost your more to purchase a liquid cooled engine in the "used" quad market and they are a little more of a nuisance to work on due to water in the engine and the extra hoses.

/Jon