I'm not an outrunner expert either, but from what I've read an outrunner can generally be a bit smaller than an inrunner and still have the same or more torque. The motor you linked will probably well in an 8ight. Here's some good reading to help you decide yourself.
http://www.rc-monster.com/forum/showthread.php?t=27799
Yeah he put it in an Erevo, but the principle is the same. His tests with different gearing and battery voltages or worth the read though. Let us know how it works out.