I can see you put a lot of work in it.
The trailer should definitely stay in the race models.
For the showroom, scaling the model down to fit will make details very small.
If you don't have the trailer the truck can be larger and you have more vertices to possibly add more details.
side tank and the exhaust pipe and some line below the trailer as protective bumper. And the light.
Just a thought. I want it to look good to.