I use the non-waterproof strips, if my cars get wet, the LED's are the least of my worries. 
I have done cars with bright white, warm white, amber, and yellow. The yellow would be appropriate for something like the Woodside passenger cars, amber I'd consider for heavyweights, and warm white for most others. However, newer cars that would have florescent lighting can use bright white for a prototypical look.
