I think you are moving in a good direction, it's similar to the route I am taking. By buying the radio now you can learn to program it with the Axe. Then when you install the radio into your Trex you'll have those "tools" (experience) in your "tool box" (brain). You might decide to buy another receiver so you can have both ready! Save you money for another month or so if that what it takes and go for a seven channel.

I would continue to learn and abuse the Axe if you can. The parts are abit more expensive than Trex parts but it is a simpler head and easy to set-up. I am near the end of building my first Trex (450 SCF) and I can't imagine not having the Axe build/fly/repair experiences to work from. (That and alot of reading around here and other sites.)

If you buy wisely you will be able to re-use alot of the electronics.

RWW