I sometimes wonder how specific models of cars have varying insurance groups. If I can give an example, about 2 years ago (before the current new-style models arrived) I was comparing prices of Ford Fiesta's.
The 1.6 Ghia 5-door cost around £13,000 with an insurance group of 7.
The ST 3-door, which has a 2 litre engine, cost exactly the same amount on the road but yet this model had a grouping of 14.
Now I understand the ST is a higher performance car than the Ghia, but assuming they were both written off in an accident, they would cost the same to replace so why such a difference in insurance groupings.
To be fair, these were Ford's own quotes so perhaps the difference wouldn't be as great from an alternative insurance company.