It will cetainly improve the car on speed and ride and cornering.Dont think the Insurance will charge for that really.Fit them you will notice the differenve straight away but you may have to play with the tyre pressures on the front.I suggest 2lbs per sq in below the recomemded and only check when they are cold.No big deal go for it.Not forgetting to paint the brake calipers red.Amorite one coat.