Hi Tom(and everyone else),

I also don't think this is a lateral location issue.

I'd be checking for front spring eye bush wear, too much front toe out, Uncouple rear springs to prevent bind(I can help with this). Check rear toe(you want toe in) ensure enough bump and droop travel at each corner. Check all the Caster rod bushes, ball joints, tie rods and steering box for play. And lastly, it may need some more rebound in the shocks.

Putting the watts on my car made a significant difference to knowing what the rear was doing. It didn't initially give me more speed but gave me the confidence with predictability in the rear that enabled me to drive it faster. But as Retrorally has touched on, any lateral location device MUST be a lot more rigid(rod ends etc) than the spring location.

The other huge advantage is you can very quickly adjust the oversteer/understeer balance. Mine has a ball screw adjustment that takes less than 30 seconds to change.

My car used to do something similar. Mine was too soft in the rear and the second it lifted the front wheel, the outside rear would overload and would snap oversteer.