Can't recall how much caster my car has, but it's not a great deal.

Caster or no caster, if the rear is flexible and has bump steer, it'll feel like it does regardless of what the front's doing; drive like an unstable forklift truck.

Your right just checked the bump steer and flex on the rear suspension with
Laser 4 wheel alignment and it's horrendous I would say just pushing the back down with the shocks on their softest setting it's moving 2 mm each side the if you put a bar in the wheel and pull another 1mm
On a better note the front didn't seem to bad

Understand the root cause before you start anything
 

I read through this thread with interest and with a bit of understanding.

Before you start a very expensive project to correct a handling factor you need to understand what is wrong!

My 5Exi is fresh on the track/road and my first outing at Llandow it performed extremely well.

I had the rear uprights massively modified by TD and then TD set it up and I has hardly been touched during the build and since the track outing.

You likely know now how much TD will charge for an assessment once you have invested the few hundreds you will know what is wrong and you can make a rational decision

There is the 5Exi location map and the registration data base you can refer too to find others close too you to look at

I don't disagree with a bike engine'd project but my std VVC is close to as fast as I want it and I have the suspicion that if you don't fix the root problem it will only develop differently with a different weight distribution.

My two penny worth anyway.

Just to let you all no I fitted the new marlin rear suspension to the car
And took it out today and the car is totally transformed
Over takeing cars no scary wobbles it now drives like it should
Well chuffed:biggrin1: :biggrin1: