Edit:
Forget everything below - you have a sweet new $250 plane and you're trying to shave $40 off your motor selection? DON'T DO IT! Hackers can be run over their limits, are made very well and have great support! Start with the recommended prop, and prop up until the Hacker is getting warm, or do some research on what people are running. Don't put a garbage chinese motor in a nice aeroworks plane, it's a sin, and is NOT going to give you the great 3D performance you want for very long. It's a $40 difference, that's next to nothing in this hobby. If you can't afford it, wait to build the plane until you can, it will be worth it.
The process I would go through:
1) suggested motor from the aero-works website: Motor Hacker A30-12XL
2) specs from Hacker (aero-model.com):
700W, 700kV, 1.46in (37mm) diameter, 6.3oz weight (176g) (
http://www.aero-model.com/Hacker-Bru...-A30-12XL.aspx)
3) it should fly good with the suggested Hacker, so I would only go slightly over the kV, keeping similar weight and diameter (the diameter is a big factor in keeping the motor cool).
Of what you suggested, [link=http://www.valuehobby.com/power-systems/brushless-motors/out-runner-brushless-motor/emax-gt2826-860kv.html]this motor[/link] is basically the same size and weight and rated for more power than the Hacker (whether or not you can run it that hard and have it last, well, there's a reason it's not the same price as a Hacker).
So, this motor, with the same batteries and same prop, will give you more power due to the higher kV. You can theoretically prop it up, too, since it's 'rated for higher power'. HOWEVER, this motor looks like it's made out of a recycled soda can and used chewing gum.
The 920kV motor will force you to prop down. You really get better performance (efficiency) if you use lower rpm, higher pitched prop.
The other motor (800kV) looks a little more robust. It's a little heavier, which again helps deal with cooling.
What would I do? Buy the Hacker. It would be a darn shame to stick such a crappy motor in a sweet Aeroworks plane. You are probably going to smoke one of these motors in a matter of flights, if they even perform enough to get you off the ground. There is a reason they are $30.