I've been wondering about insurance lately myself, as I've begun doing some major upkeep and the $$ are adding up, but if It gets flattened by a Freightliner (hopefully I won't be in it if it does) they'll write me a check for a hundred bucks and say "here's your truck"
Keep receipts for parts changed or added, they usually won't allow YOUR labor cost but if shop does the work in can be included.
I lost a 1992 Ranger 4x4, hit on passenger side front wheel making a left turn
Because it was 4x4 the insurance totaled it, they look up similar vehicles with similar miles to get a "replacement" value, then added my receipts from the last year to that, brakes, hubs, u-joints, ect..........
Also got a bit more for tires since they were only a few years old
Remember you are negotiating the payout, they make an "offer", its up to you to accept it, so have a counter offer ready, with some proof i.e. receipts, or proof of replacement engine, trans, new clutch, new tires, muffler, cat ect............
And also remember you should be paying less monthly/yearly for insurance because vehicle is not worth $50,000