You're not comparing apples to apples there. Don't buy a prewired kit. If you are at all comfortable (or even just interested) in DIY projects, the wiring isn't such a big deal.
As for reflectors, to the best of my knowledge, ice cap does not make a 36" reflector, so you'd have to trim them. This isn't difficult either.
I am currently building a 36" Tech 70. If I were going to use a canopy I'd go ice cap. Since I will not have a canopy I'll be going with the 36" Sunpower.