I've just insured a Fabia vRS at 21 with NO NCB because I was always on my dad's insurance! it does go slightly down when your 21 but looking at quotes etc it won't go down a great deal until not classed as a young driver (17-24 according to most insurance companies that i looked at). I also found out to my annoyance that most Ins comps will only insure someone of this age on a vRS with 2 years NCB. However I got mine fully comp in my name for 800 quid. At 21 with no NCB i thought that was a decent deal.
BTTT i bought a vRS because it ticked all the right boxes fuel economy,m speed, number of doors, modification potential etc etc.