If you ever need to make a claim to your insurance company and you have not informed them of any changes to the car then they can refuse to pay anything.
It should be worded in the small print in your insurance booklet,if it's not mentioned, or you simply cannot find it, give them a ring and ask them.
Better to be safe than sorry.
1 litre Zetec Turbo petrol 74Kw / 100 Ps. as in my avatar.