depends what you want from it really.

if you cain it all weathers and arnt bothered about power over stage 3 then 4wd

if you like tyre smoke, burnouts and drifting then 2wd

as to which will be quicker, standard 0-60 4wd wins (i think cant remeber off the top of my head), in the wet 4wd wins, in the dry generally 2wd wins

back to the wet vs dry though, youve got to remember that its a ford so any time in the rain and there will be no sills and arches by the time you get home , and how many people really push it in the wet????
rwd will only step out if you make it