There are some slight differences between 05 and 06. Most of the 05 models got new, larger brakes, but the 05x retained the 03-04 brakes. Both brake setups are outstanding, among the very best on a production vehicle (60-0 in 113 ft). The old setup does it with grippier pads that wear out quicker, wear out rotors quicker, and produce a fair amount of brake dust. The newer setup does it with larger rotors and twin-piston calipers up front.

All the 06's have the larger brakes, including the x. And the 06's also got bluetooth. Some of us with the 05x have upgraded to the larger 05+ brake setup (as it's called here). It's a (mostly) simple bolt-on upgrade. You can often find the larger setup for sale in the Marketplace ($300-ish for a complete setup). If you want an AWD, think about getting an 06 and save yourself the hassle. If you want a RWD, the only difference is bluetooth.