Ghia escape velocity
 

I have read different threads on beetle airodynamics- when they want to become squirrelly and then airborn, But not much on my car, The Karmann Ghia.
Once the suspension is stable, (no loose steering boxes or worn ball joints etc) When does the ghia want to drift due to becoming weightless? With bugs I have heard around 90 MPH but there are alot of 12 second Bugs breaking 100MPH in stock form, (some even lowered in the front which some beleive makes the problem worse), and alot of these Bugs weigh less than stock which I'm sure doesn't help keep them planted on the ground.
Anyone have a ghia that has gone fast? Shad? Anyone?

Thanks
Ron