re: the 'white spots' (its a tropical fish disease too y'know lol) - I noticed this at the weekend doing rods skins.......if you save your PSD as a DDS then continue to work on it and save it again as a DDS, the white spots appear (for me anyway, this was in max, not rf, but looked exactly the same).
I got round it by basically closing the dds after i'd converted to it from PSD, and re-opening the PSD to continue painting....it seems to be if you save the same file twice as a DDS it corrupts it.
hope it helps
ps - MoR, is there any plan to set up a number list? given there's people racing RF 1s who aren't UK Dirt members, i'm concerned there'll be skins over-writing skins if the number database isnt 'centralised' and (as an example) you get 5 FWJ fans who all paint '515' skins and then save em as 515.dds or whatever, or is the skinpack intended to be UK Dirt only?