If your car is a fairly normal road car, I’d suggest you place the centre of gravity (CoG) at a height of about 0.4m above the ground plane. Using tyres that behave like real world tyres this should slide before it rolls (unless you hit a trip obstacle).
I think it would be better to fix the CoG position rather than compensating for its effect on the suspension displacement measurement.
Is your mesh volume centre a large distance from the coordinate system origin for that mesh? Unfortunately, I am once again guessing here, as I have no UE vehicle experience: I’m sure that the mesh volume will be used to calculate the rigidbody inertia tensor - I’m not sure if UE uses that to re-calculate the CoG.