AP though excellent are overpriced imo, if you don't need this level of performance ther eare many less expensive options dependant on wheel size, std 4wd calipers are really only man enough for a action man car!!
Using the 2wd 4 pots with mounting brackets and FRS 324mm discs will give a huge benefit for the least money, sure reyland does the brackets and spacers for the calipers(body).
tabetha