Yes, that's a known limitation: the physical model is separated from the 3D model, and we don't know where it is. The problem with the wheels is the game will assume the first two polygons on the list (or the first twelve vertices, I don't remember exactly) are the front wheels and will use them for coordinate transformations - and thus you might end up with the nose of your car being steered as you turn the wheel.
I recon there are two good options:
1 Every car uses the same simple physics model. This one seems unlikely, the lancia does appear to really be shorter than other cars.
2 It has something to do with all those parameters that don't have an explanation on them in car blaster. Some of the series of bars really are shorter for shorter cars. However, that could be more of a result than a cause. I'm going to look in to this one when I can find the time, put it's gonna take some puzzling, since at least some of these series appear to have limitations on how much or on which sides you are allowed to shorten them, plus I've already played arround with them and now my kart is heavier or something like that on one side, landing on two wheels after every jump.
If that's not it, I'll live with it.