03 A4 quattro 5spd

i have this rattle that starts @ 60mph and increases with speed. I installed hotchkis sway bars which makes the car ride a bit rougher so now there is this rattle. the rattle was there previous but only on pothole bumpy roads. on a long drive it is unbearable even with music all the way up. its really hard to pinpoint where it is. it sounds like its back behind where the glove box is, was. i will have a passenger check while I drive next time i get a chance.

i removed the glove box. ruled out the cup holder. shaked and smacked the heater/A/C assembly. popped off the door panel. didnt notice anything that looks like it is rattling or lose. i guess the next step is going to be pulling out the hepa filter assembly and anything near it, or maybe take the dash off. maybe it could be something tapping from the engine compartment side of the firewall, but i dont see anything loose there and itsounds like its coming from inside.

any ideas of what to check? everything that i didnt remove looks bolted in solid and passes the bump shake smack test.