Wet Sanding Water Marks in Black Paint

This is a black E39 M5 that I restored in a full day. However, I decided to work the trunk last because it had water marks and "Bird Poo" stains burned in. (At this point in the job I was completely exhausted but wanted to get it on camera as I've had a bunch of questions about how to remove this type of damage from viewers.) Also, I'm trying to prove a point that a microfiber cutting pad can remove 2500 grit...which is CRAZY! Normally, I would wet-sand the panel to 3000, 4000, and even 5000 before attempting to remove with a microfiber pad. At this point, I'm testing the cutting power of the pad to learn how strong this particular pad was. (Normally, a wool pad would be used for ease and speed in this case) Remember there are 3 levels of water stains. This was level 3 or the worst stage. Level 1 is when you leave the car outside in a quick sun shower (or sprinkler) and it can be wiped off with spray wax. Level 2 is when you need to use spray wax and a clay bar to remove the contaminants. Level 3 is when you have to level the paint (wet sand or compound) to remove the stain.