What frameset is it TrekCommuter? If it's not a Grand Tour, as stated in the subject of the thread, and rather a Gunnar Sport, this shifts to more of an apples and oranges comparison. The Sport does come with a set of eyelets at the rear dropout, but is less of all-around tourer than the Trek 520.
OP: I think you are taking a pretty sensible approach to this which is quite important if you're talking about needing to sell things to afford this. You know your position better than anyone else does.
The frameset *is* important if you are wanting to run panniers on the back with 42cm chain stays(heal-strike) and a rack on the front with no eyelets. And/or you were looking for handling more like a Trek 520 but we're talking about handling more like a Trek CrossRip.
I've had good luck with a pair of Alex wheels I've hammered on my cyclocross bike, but that doesn't mean the Ace-19s are any good. We'd have to know what your touring aspirations were before we could weigh totally in on the components with any validity. The borrowed gearing would be fine for some tours, perhaps not fine for others.
If the frameset is like new, it's the Grand Tour, and it fits you nicely…I'd say it's worth the asking price, but I agree on offering about $1,500 for it and seeing what they say.
Edit to add: Gunnar will tell you more about it from the serial number.
__________________
Ron - Tucson, AZ
Last edited by Miles2go; 08-11-14 at 11:37 PM.