Underneath mine is as I bought it from your brother, I had a basic alignment done, with -2.5 degrees of camber and that's it. I've faffed about with the dampers, but it's mostly middle of the road type stuff, softening them off if it's wet outside. I usually aim for around 30psi when hot in the tyres, I tried 28 at donington and the car felt a bit better than it did at Cadwell. Currently R888's which I think when comparing to other R rated tyres are pretty terrible things. The nose on mine likes to push a little if I go in too hot, but it can be driven around. I am in no rush to change anything underneath the car at the minute. Mine has a full weld in roll cage which I'm sure makes a difference to the cars handling characteristics. Have you had any instruction, it could be something you're doing to unsettle the car.