Thanks for the information Cheeky chops, please let me know how the Ohlins fair up.
I have already voiced my concerns re speed bumps, and had a few replies, which do not seem to be a problem. I have Ohlins fitted to my motorbike and they are great, and must admit to being tempted, but if they are really only for the track then I will stick with the standard set up. Same goes for the exhaust really, I will stick with the standard then pick up a full system provided Vauxhall will cover it on the warrenty.
I noticed in Top gear the VXR is car of the month

, also noted that if you look at the pictures there are two cars involved, so for those interested.
VXR No KE04 GYH Featured in top gear Mag
VXR No KE04 GWW Featured in top gear Mag
VXR No KE04 GWX Driven by me at Sandown
Ther is also a write up of the VXR with pictures in car Mag