£880 a year to insure a car worth £1800 ?

My insurance has shot up cos of my silly TS20, but having said that its only £100 cheaper without.

so £780 for a golf vr6, civic type r (same quote, even though one is worth 2k and one is worth 5k?)

Why is insurance so silly ? Never claimed have full ncb and im 24.

Wierdly, to insure a UK TT Supra, which are

rare
3hundred odd bhp rwd standard
higher group
cost £12k, thats twice the civic and more than 6 times the cost of the golf
is £780 fully comp

Makes absolutely no sense to me!!!!!!!!!!!!!?

Also, how do you get insured fully comp on two cars ? So you can run a daily and a weekend car ?

Thanks