I have a 2001 Brava 1.2 80SX which is due a service. Is there any noticeable difference apart from price on an ordinary air filter or a K&N filter?

Also if a K&N filter was fitted would you have to tell your insurance company?

k&n sucks in more air and supposed to give you a few extra bhp. as for insurance no you dont need to, if you did they will prob increase your insurance for the fun of it..