xx is the new ultrasupermegalight xc only stuff. the xx is 288 grams and the xx wc is 279. both weights are with 160mm rotors. they have 140s out for them to save even more weight. to give you an idea of how insane that is, a speed dial ultimate lever and single digit ultimate brake setup without including cable and housing is 262 grams per wheel. so the hydraulic system weighs 34 grams more than the cable system WITHOUT the cables. that is crazy light.
as far as the brake lineup goes, i dont see them keeping the juicy 3 for more than another year tops. then you have the elixirs, codes, and x series. not really that confusing, code is dh/fr only, x is xc only and elixir is the middle ground.
it might be easier if sram aligned the names more though. the elixir cr is the x9 equivalent, the elixir r is x7, the 5 x5 and the 3 x3. i wouldn't be shocked if they slowly do this over the next couple years, but they cant just drop the elixir name overnight just as its building brand equity.