They can actually as it states, if you dont declare your mods your uninsured in the same way as if you insure the car in someone elses name and drive it around every day, happened to an old mate of mine a few years ago, 1.4 astra with a 2ltr redtop in and it was !Removed! quick too, they siezed the car to go over it all and then gave him the option to pay the fine of impound and he had to insure it for what it was to get the car back. there are alot of corsa around here that are driven by young uns with redtops and even saw one the other day with a turbo engine in, i for one would be pretty !Removed! if they lost talent and smashed into my scoob to find they wasnt insured... im sure everyone would feel the same.