Anyone have stock HK Speaker Upgrade options and reviews for sedan?

[Fried_Chicken]

I am excite

[Mless5]

Does anyone know, what is the maximum depth of the speaker that can fit stock opening IF the protruding lip on the door card is shaved down to be flush with threaded inserts?

[Fried_Chicken]

Here's a thought: What if the Stock HK sound system is actually amazing but nobody has refreshed the speakers with brand new ones from BMW?

Does BMW still sell the parts? Does it cost a small fortune or is it reasonable?