Sounds fun - is it a supercharged 2.2 or the OEM turbo?
Why are you looking to swap? I have a Westfield as well as my ///M and I use both on the track as often as I can. They offer completely different driving experiences and I wouldn't want to have to choose one over the other. My Westfield isn't as powerful as your VX but it's lighter so it must get better than 45mpg
Loved the VX when it came out, think it was about 2003, Managed a passenger ride in one at Castle combe, Press demonstrator at full chat, The guy managed to spin out twice, with me aboard. Fantastic fun. Alas I'm too tall to actualy drive one.