Are they bigger than the xB ones?
Yes, they are taller, wider, and longer. The piston size is the same though, so it shouldn't impact the pedal feel.
xB2 brake pad is 139.2x55.5 and 17.5 thick (mm)
TC2 brake pad is 146.6x56.6 and 17.6 thick (mm)
I'll bet the xB2 calipers will work with the TC2 brackets, but I've found that it's much more cost effective to by calipers with brackets (no one wants to separate them).
Now I'm just trying to settle on rotors. I can get cheap blanks for just over $50 a pair, but I'm wondering if I should spent a bit more on something a touch nicer. I don't believe in the gimmick of cross drilled or slotted, but I know there are better quality blanks out there. I wonder why the seller I got the calipers from isn't selling the rotors as well; looks like they are parting out a whole TC and the car only had 5k miles on it...
Edit: A note on pricing, it looks like I will be able to sell my calipers alone for as much as (if not more than) the TC2 calipers, so this is going to end up being a very cheap upgrade (probably well under $100 when everything is done)