As long as it is part of the car (attached) they are supposed to cover it, where you run into a problem is when they decide it's cheaper to just total it rather then replace your parts. Sure they'll give you the value of what the car is worth, but your out for the rest... go ahead, as me how I know.
It's not really to much of a problem unless you start spending a ton of money on it, and apparently I still haven't learned my lesson because it looks like I'll be doing it again with the Z
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"At no point during your rambling, incoherent response did you ever come close to anything that could be considered a rational thought. We are all now dumber for having listened to it. I award you no points, and may god have mercy on your soul."