@Todd M- I forgot to add that irs trailing arms can be narrowed (I've heard of as much as 1 1/4" per side and not having to narrow the torsion housing), but it is a little involved, and then you have to come up with shorter axles (type 3 automatic left side is approx 1" shorter than beetle sedan irs axles and works). The point is if you want it bad enough, whether your car is swingaxle or irs you can put somewhat wider tires on the back of a classic Speedster bodied car.