So, this started my journey into modifying things – and mostly because in the process, I lost one of the grill stickers, and still cannot locate it today. I ended up vacuuming my room and who knows if it even exists anymore.
I tried to replace the grill with other materials – mainly craft felt material and varying amounts of cut up ear bud foams. I ended up sticking with a small amount of the ear bud foam that I cut a square out and rolled up and inserted into each nozzle. This actually tames the treble peak slightly, while also keeping the upper-mids and lower treble similarly, if not identically, to the stock grill.