Insurance is a pain in the rear
Have a look at this thread, I had major problems when it came to insurance for my MINI ONE (despite it having already been insured, or so i thought)
http://www.mini2.com/forum/finance-i...ules-long.html
Basically as I understand it, and have been told the same by a few different companies (MINI, Churchill, Zurich) Anything that is not part of the spec of the car i.e MINI ONE Pepper in my case is classed as a modification. My alloys ive been told are ok, as they form part of the Pepper pack (though im sure they would change their mind

)
For my car the 'modifications' i have listed on my policy with Zurich are, Rear Spoiler, Side Skirts and Decals....this was after numerous discussions and phonecalls and eventually the guy at A Plan saying thats all that needed to be put on it

(it even got to the point of me getting him to sign the piece of paper with it on!

)
So yes, you will need to tell them about the GP alloys, any decals you may have, a spoiler if it has one, things like that....