Bear with me, this might take a while! The general consensus seems to be that the VX is a good 70-100kg heavier than the Elise. There have been numerous posts listing where the VX is heavier.
The latest Vauxhall press release states kerb weights of 875kg and 930kg for the 2.2 and turbo, respectively. A recent thread on the Elise BBS quoted the following vehicle weights for owners cars;
early S1 700-710kg with no fuel
S2 755kg with half a tank
S2 780kg with full tank
S2 765kg with no fuel and aircon
There was no mention of the driver being included in these weights!
Anyone know if the weights quoted by Vauxhall are kerb weights? EEC kerb weight is measured with a full tank of fuel, all fluids, spare wheel and toolkit

and a 75kg driver. If this is the case, the comparable VX weights would be;
VX 775kg (875kg less driver weight and approx 25kg fuel)
VXT 830kg (930kg less driver weight and fuel)
It can't be that straightforward. Otherwise Vauxhall would have pointed this out in their marketing material. I am obviously missing something. Anyone got any suggestions?