how many kilos lighter is a carbon bonnet to a stock aluminium 6?? i want to lighten the car a little come the summer but without stripping it out and taking out the hole cutter!! do these still fit right and lock with the original catches?? (security) and id plan on painting it as i dont like the (multi colour) look, or would i be better off with fibre glass?? again same questions as above, and who makes FG ones and prices??