it's a bit more complicated than that. We run groups from 1 to 21 - 1 being cheap and 21 meaning you need to be very well off. I'm sure the new WRX is either a 17 or 18, so fairly high up the scale
It also takes into account where you live, where you keep the car during the day, during the night, if you drive it to work, how many miles you think you'll do a year - and most importantly for you your age. As i said I'm the same age and have really struggled to get a quote for my Impreza under £1000, the whole reason it's taken me this long to get one is because most of the main insurance companies won't touch young drivers in Impreza's unless they are box stock UK models
Import cars are even worse, as they need to go through an SVA test to ensure they are UK legal - which I think I remember is fairly expensive. Then the car will always be classed as in import which will add yet more cost to the insurance
IMO you'd be better selling up the stuff that you know you can buy here