Yeah, really helpfull post there
Avoid XTR calipers, they are far too flexy for trials.
Avoid Shimano levers, they are also flexy. (Other members swear by XT or XTR levers because of the comfy shape and feel, but if you want maximum performance then Avid SD7 is the choice.
Avid calipers are great, very stiff. Deores are supposed to be good but I haven't tried them myself.
DO get a STIFF booster, will massively improve the hold of the brake. XTR carbon V booster is brilliant
DO get a linear brake cable, makes a massive difference to the stiffness and power of the brake.
DO get an SD7 lever as mentioned above
DON'T expect a V to work like a Magura, the bite will never be as good no matter what you do!