We spoke about this in an earlier thread.
Some of us assumed the tyres were directional and sloped. ie. tyres slopped from side to side to make the right hand side of the car lower (in Australia) so that the car travels flatter on a road that cambers down to the left. I had a friend who cut the springs on the RHS of his car to do the same thing. Never seen these tyres before but just assumed thats what they were on about. If thats what they are then Amercian ones would be unsuitable here as the road cambers the other way (we drive on the other side of the road).