I had a similar dilemma to the OP when renewing my insurance last year. An uprated Cam on my mk2 was pushing up an already rising premium, which annoyed me greatly having never made a claim in years of insuring one or two vehicles.
In the end I decided my concience would bother me and that I would always be worried if I didnt declare everything, including parts that would require engine stripping to be discovered. After an afternoon of ringing round insurers I ended up with a better price, and was happy enough (went from Adrian Flux to Sky insurance).
So as has already been said, it really has to be viewed as part of the cost of mods. What I did start to consider was if its adding so much to insurance, would I just be better off buying a 'faster' standard car, Insted of spending money on my mk2....?
That thought soon faded on the next fully insured blast around the back roads!
