RE: Tamiya Sand Scorcher, Buggy Champ and Ford F-150 Ranger
Very cool.
Whether or not you take it out of the box comes down to what you want out of your collection.
Personally, I would leave it in the box. But if you would get more enjoyment out of your collection by building it and having the build models, go for it. Just realize that sealed box items are generally worth much more down the road.