Insurance will be different depending on the individual. Takes 5 minutes to checkout online with confused.com. Daft question to ask tbh.
The tax can also be checked on DVLA website, but with being an import will depend on how it's been registered. If its reeks tested legit then will be £149 for 6 months and £290 for 12 months.
Running costs of a DC5. If you're worried about that then you shouldn't consider a performance coupe. All depends on how driver but should see between 25-30mpg on average. A remap would see it better.
Seller - would you be interested in a deal with my E46 320D M-Sport that is also advertised on the forum, with some cash going your way?