So the question really is, what's a stock 2300 worth? The hybrid aluminum lug/carbon tube frame is very good at damping vibration from road surfaces, but the ride is a little dull if you're used to a lively steel steed. Keep that in mind.
In my area, the ones without brifters go for around $250, whereas brifter models can go for $300+. But that's about it. Older hybrid alu/carbon don't get as much love these days. As far as yours? No clue. Extensive customizing will not necessarily increase the value.