My guess is that the BD bike might be a bit heavier than 22 lbs (but not too much).
The BD bike will have a more aerodynamic, aggressive position. That should mean faster high end speed, but if your body doesn't like the position, then that's not a positive.
I'm not a big fan of 23c tires on the BD bike, but if you only ride on good roads, you shouldn't have an issue. The BD tires will likely roll faster than what you currently have on your Trek.
If you have your Trek tricked out with lower handlebars/bar ends and faster tires, you might not notice much of a difference at all on flats; I'm assuming the Trek is heavier, but depending on your weight, that may or may not be a big deal (it wouldn't be at my weight).
It's not a crazy choice; it looks reasonable enough for a entry level road bike, if that's what you want. It would be noticeably different than the stock Trek. It may not be very different than a highly modified Trek.