It all works on statisites, so they may of had more claims from drivers in st170's. Insurance is quite strange in how it works, i'm 19 with 2ncb clean license and i had my volvo 850R insured for £990 (which for my age is ridciously cheap i my eyes) fully comp and thats a group 18 car with 250bhp standard and limited to 155MPH, its mad how it works!