First car for 23 yr old male driving one year needs car that can cope with regular motorway speeds comfortably?

im stuck with what car to buy. i would have been driving one year soon and im really stuck with what car to buy as my 1st car, it must be able to cope with motorway speeds comfortably with some extra power for overtaking as the majority of the 6 - 10 k annual mileage will be motorway miles. it has to be light on the insurance and under 4 k - 6k including insurance. any ideas ??