it diesnt really matter two much what the vehicle is in regards to say an astra van or astra estate as they are nearly identica in the eyes of an insurance company

the main thing which will affect it is use ie if its gonna be used for business or social demestic and pleasure as the insurances are calculated diffrently plus on commercial you get things like public liability etc

but ot say this some insurance companys can get funny about insuring a van but there are just as many who have no issues so should not be any trouble to find a quote at a resonable price depening on what you have done to the vehicle (ie mods etc)

and if you were to weld up the window sections of a car it would still be classed as a car to the best of my knowledge