Modified car insurance can be expensive, mainly due to the cost associated in replacing the modifications on the car if they are damage in an accident or are stolen. If you have modified your car by increasing the BHP in the engine (for example, via a re-map) then you may find that your modified car gets classed as a high performance car, which is any vehicle that is given an insurance group 34 or above.
Insurers prefer to insure modified cars which perhaps have been modified in order to keep the original spec of the vehicle. For example, if you own a car where the engine has been uprated following an engine replacement.
It is vital when buying car insurance for your modified car that you disclose all modifications to the insurer. Although it might cost you a bit more initially, it won’t cost you as much as it would do if, for example, following an accident you find that your insurance company will not pay out on your car because they find out that they have ended up insuring a car with modifications which they usually would not cover.
It is far better to be upfront, and then have the peace of mind knowing that you are correctly and fully covered. You may also be at risk of getting a conviction for no insurance if you do not disclose all of the vehicles modifications to your insurance company.