S197Probie brings the tech. Nice post.
You can swap parts out provided the appraiser knows and it does not affect the value. Generally, insurance views alloy wheels as alloy wheels; we don't much care if they are OEM or aftermarket. Doesn't make much difference to the value of the car overall. Cold air intake? Adds nothing to the value; go ahead and swap it out. Just don't take something out of the car and not replace it with something...had a guy tear out (literally) his aftermarket radio, ruining the dash in the process. Not only did we gig him for no radio, we also deducted the price of a used dash, because he damaged our salvage (we pay for your car, we own it). This is why I rarely sell off my stock parts when I build a car that is street driven; swapping stuff back to stock pays me more in the long term.
As for the hail damage claim...(sigh)...if your area was hit hard by hail, and they are doing a LOT of cars, then yes, estimates tend to be written very poorly. I don't like it, but the usual mind-set of the company is "Just write something and pay them; we'll work it out later". The Ins Co wants to look like they are a hero by handling the claim quickly. The appraiser KNOWS the estimate is crap, but that's what he's told to do. I think it's stupid; it makes a hell of a lot of work cleaning it up later on supplements, but you are somewhat right...a lot of the claims wind up never getting fixed, so the Ins Co saves big money. But, if you fix the car, they will deal with the big supplement when the time comes. This mess usually happens under 'catastrophe' rules and when you're looking at writing literally thousands of cars like we did a few years ago in Arizona, you quickly learn not to care too much about accuracy. Get 'em in, get 'em out. I write hail claims very differently when I've only got 10 of them to do.