The FTW3 has a higher power bios, 373w vs. 338w in the XC Ultra. The Ultra is the same basic card as the XC gaming, they are both reference cards with A-chips, so if you're not going to use the cooler, just get the normal XC gaming. The FTW3 doesn't have any better chip binning than the other A-chip cards. There is an option to flash to a 380w bios on the reference cards, or even higher maybe, but there's considerable risk in that.
Lots of people are panning the hydrocopper blocks and saying the aftermarket ones are better.
I'd go with the XC gaming and a reference aftermarket block.