. . . check with whomever is putting on the contest.

In some events, 'box stock' means you can't add anything that didn't come in the box. You must supply the instructions so the judges can verify that you didn't add anything and you didn't swap wheels or something.

In some events, paint, decals, foil, and flocking or embossing powder are okay, but in some other events they are not.

You just have to go with the rules of the event, otherwise your model will be sitting on the sidelines.

Same can often be true of other classes or categories. Our event requires "street legal" in many classes. That means models representing vehicles that would be street-driven must have the same legal equipment that would be required of a 1:1 -- lights, signals, mufflers, license plates, wipers, etc.

One thing that trips up a lot of would-be contenders is absence of essentials: transmission, drive shaft, springs, shocks, exhaust pipes, etc.

All of this generally depends on the class. Obviously, we don't require or look for mufflers, wipers, turn signals, or license plates on Formula 1 cars or Top Fuel Dragsters, but they should have the essential components of their ilk.

Most often, by the way, in our event none of the above (except the 'box stock' or 'out of box' criteria) necessarily eliminates a model from competition, but these are very often the fine details that mean the difference between scoring hardware (awards) or not.