From my experience ~~ a long time !!!
.Most of my cars have been competition cars,or very highly modified.When needed to be put "on the road" for various rallies.I have used a a specialist insurance insurance company.I declare everything,right down to the brake pad material :approve: .I then know,that I am 100%
.Legal.On two occasions (different cars !) I have had accidents,resulting in Total losses
.What a pleasure when the inexperienced assessor comes and tells you,"but this is modified !!!,yes but this is the sheet ~~~ engineers report ~~ YOUR insurance company requested ~~~ Now go away and send me a cheque,for the full amount ~~~~ Worked every time.One of the times,I ended up with the salvage and some cash
.
Like most things relative to insurances,houses cars or whatever.They gladly take your hard earned cash in premiums,but are reluctant to pay out.You can be be lucky and get away with it,~~~ or unlucky and lose the lot.My advice for what it is worth,declare everything,Non ~~ original parts ~~ including wheels,seats the lot ~~ it is only a letter to the insurance company ~~~ could save you your car.