Ok, good start. The perspective seems off in some places. The fin(?) and end of the car don't agree with the other angles. The tan color on the wheels is quite odd looking, and I beleive it should be changed.
As for the pallet, I am not too sure which direction you should take with it. Try something which the blues of the mountain look better on the sand (at the horizon line).
And to answer your question, as color count decreases, it is not exactly a true corralation with detail. Some artists can accomplish a lot with small ammounts of colors.