First of all, unless you can find tech sheets from the actual Tech inspection, (or publications by the race organization like those in the old LM24 books) dimensions are always prone to interpretation.
Like for width sometimes they measure cars with wing mirrors, sometimes without...makes a difference.
Same goes for overall length, differences between road and race cars can be from measurements taken with or without front splitters and rear wings.
Overall height is even harder to determine as in some classes (like GT3) the ride height (ground clearance in slot speak) is part of their B.o.P and may differ per race.
Then there's the topic of this thread, the BMW M4 GT3 of which allegedly, the front and rear windows are the only body panels that are identical between the road and the race version.
with kind regards
Tamar