[Yaw]

The issue is not the modification/s, its what the policy covers.

Once a car is modified beyond the manufactured specs it can lead to other issues.

eg. put a bigger motor in , a lot of the time the brakes and suspension won't get upgraded also.

So the insurer is not able to make an informed decision on what they are covering.

Then what the policy states can become a big disappointment (fight) for the owner should something happen.

Eg most policies will state that parts will be OEM (original manufacture specs) or aftermarket to the oem specs.

So lets say you have fitted a sports exhaust, when an accident repair comes, you will only be entitled to the original spec parts, meaning one of a few things may happen,

The insurer may void the cover, refund the premium as if the policy never existed stating had they known in the first place, they would never have offered cover (this comes down to your duty of disclosure)

Another option the insurer may take is to just pay what the original spec repairs would be and have you contribute the difference

or just simply make a cash settlement to you which will not be enough to fix the modified damage also.

As you can see and if you put yourself in the place of anyone like this, the customer is not happy and starts bad mouthing the insurer as they feel "ripped off" so a lot of insurers simply will not take the risk on in the first place.

This is why you pay large premiums on modified cars.

A quick example of imported car premiums can be the policy may state if parts are required, they will come by sea.... Meaning if parts are needed from overseas, you will need to wait for a boat to show up with them, they will not pay air freight to get the part sooner, making the customer unhappy with the time frame of the repair due to waiting for parts.

I hope this helps give some clarity to you.