It won't cost more to buy a diesel, it's 1 insurance group higher so minimal and mine is worth about £1300, a good diesel is about that.....
It's hard as I'm also considering an 100hp, mad I know but I'm thinking if I'm getting 220 from a tank now I could have a car that gives me pleasure for that, or I could just go for a diesel and get 50mpg......
90% is city driving