If your car gets stolen and you have underclared mods, the insurance can refuse to pay as the mods are what made it a more attractive target ie wheels, bodykits etc.

If you have an accident and have mechanical mods including wheels, brakes, suspension then again, they can claim that the wheels will have a played a contributing factor, ie not what they came with from factory so not recomended by a manufacturer.

As said, depends on the insurance companies view, but if they have any excuse not to pay, then they wont.

If the assessor has not yet visited, get the wheel off and some standard ones on there.

The downside for you is - short term fully comp and had the car six days? the insurance will view this as a little dodgy.