Sorry mate, not meaning to put you down.. but "official Heckler & Koch approval" does not count for a lot in airsoft. H&K makes excellent firearms, true, but their interest and knowledge in airsoft is questionable.
Again, not saying automatically all Umarex are bad. just that to research which ones are good you need to find out who manufactures the gun in question, and sometimes you might even find that you can find it cheaper from the actual manufacturer.
personally I always recommend sprayed two-tone.. once legal defence is obtained it can be sanded down.