There are differences between insurers in how they consider a modification to affect the policy. Not just performance mods either. Visual mods may be taken into consideration. There are stories floating round of even very minor mods leading to invalidation of a policy or increased premiums. I don’t know how true some are though. Could just be “fake news”.
It is always worth contacting the insurer for clarification. Maybe even before the mods are made so as not to run the risk of cancellation after you do the mod. You then have to declare that cancellation when applying in future.
AWAYS read and check your documents for a policy you have just taken out or renewed. I have found errors a couple of times that needed correction. One led to a reduction in premium.
