Like Terry said, Insurance companies vary. The most popular policy is to only pay for bare minimum replacement to OEM.

The total-out value is computed by an average of recent autotrader/recycler/auction sales in your area of shitty 2gnt beaters with blown engines. So pretty much $1500-2000 is the max they'll give you depending on what company they use for valuation. The fact that your particular car was worth 10k+ is of no interest to them.

I've been posting fake 2GNTs on all the trader boards at high prices to bump this number up a little, but they probably "intelligently" remove the top 80% of prices.

The exception would be if you have stated in advance what mods you want covered and have paid for extra "riders" for aftermarket equipment like tinted glass. Also a "stated value" policy would cover the true value of the car + mods. Very few people have either of these types of policy additions because they're not offered openly, you must request them.

Some companies automatically cover aftermarket parts, usually up to $1000. Read your policy declaration carefully.

If there's a dent or tear in the unibody or rear 1/4 panel, they will most likely total it. If you don't want it totalled/salvage titled, you can say the dent was pre-existing and they won't factor it in.

Personally I've made the difficult decision that even a fully insured car that's more than ~5 years old isn't worth the amount they charge for premiums. I went back and did the math on all the claims between my g/f and I over the last 10 years and found that we'd paid far more in premiums than it cost to fix/replace the cars. And in no case did any insurance company fully repair the damage, they always had some excuse for something. So now all my cars are liability only, in case I manage to kill some family in a minivan or a Ferrari. I just put a hundred a month into a savings account as an emergency fund for each car.

Anyways, to end this fucking novel... the best weapon against any insurance company is saying NO to the adjustor's offer. You absolutely do not have to accept until you are satisfied. The longer it sits on their desk, the more money you can get. Call up their supervisor and complain if they stop/refuse to make higher offers.

Keep us updated, and good luck.