Tracks aren't yet editable, so it's a no for two of those. Tyres sticking through the bodywork is sometimes just the suspension setup combined with too low a ride height, and sometimes issues with the draw order of faces in the car model (i.e. what the game considers to block the view of other parts) where the wheels are drawn above certain bodywork elements. This is in theory fixable, but is either an accepted side effect of the car setup from PD, or extremely time-consuming to fix when it's a model issue. Maybe if the model format is understood better in future it'll be more feasible.
I'll have a look at the Unisia GT-R - does it do it with the default setup, and do the other JGTC GT-Rs do it too?
I'll have a look at the Unisia GT-R - does it do it with the default setup, and do the other JGTC GT-Rs do it too?