Yes Zinam I know that already, read the manual for n number of times, but if I am going for 15" then I am not gonna throw away my stock rims. These rims would be fitted back to my car before going to the service centre!
You got the point, Who's gonna waste the extended waranty for which we have paid for during the time of purchase.
And the service center guys wont even come to know that I have upgraded to 15"chers unless and untill I am gonna tell them!!