Im 22 years old and i insured with brentacre and they said i have up to 130bhp of mods, (standard being 113bhp) i can do before it goes up another level and i have 1 year no claims and it cost me £58 a month. They also told me that they dont charge extra for suspension mods and all that, they go by the power so its only engine mods they will charge for.