4wd for sure, best of both worlds.
i'd only go 2wd if u plan on leaving it pretty stock standard as bigger power upgrades will mean u cant get traction as easy.
so just depends on your expected power output i reckon, no point having 4wd if u only stock.
i must admit with my rs four in 2wd (front driveshaft removed) with 350rwhp didnt really spin much at all, compared to the same setup in a rwd commodore which smoked tyres at any speed, any gear. must be alot better suspension designs
cheers