I have Herrod lowered springs, and Koni shocks, which Herrod have revalved to their own specs. They fitted a KMac camber kit, which the wheel allignment guy cursed, cos he said they were hard to set up.
The Herrod settings were
Caster LF 7.9, RF 7.1
Camber LF -0.6, RF -0.6, LR -0.9, RR-1.1
Toe 0.0, 0.0, 0.0, 0.0
Tyre pressures? 34 lb all round, which are lower than I used to run, but they know better from experience.
Does handle very much differently to a standard XR8. I'm very happy with the result, except under full power in say 3rd/4th at 130 - 150, on a bumpy road (all roads here are bumpy) the car 'tips' from front to back, so much sometimes you have to power off.
AUIII XR8, Manual. Herrod Motorsport bits