While getting my initial tuning rig setup and verifying my routing through the DSP > Amps > Individual speakers, I noted that the passenger side tweeter was almost imperceptible when playing pink noise at levels that worked fine on the drivers side. This was especially odd to me since I replaced the tweeter several years ago after noticing it wasn't pulling its weight at all. The replacement was used, and I was stricken with engine timing issues shortly after (so I never really verified it was operational) but I was still surprised to hear it wasn't working either. Everything measured out fine with a 6ohm reading at the amp's wiring (identical to the drivers side), so it wasn't a wiring issue and the coil seemed to be in-tact, but still, no volume on the thing.
Whatever the reason, I decided the micro oem tweeters weren't worth wasting time on anymore and proceeded to order aftermarket replacements. For this I chose:
Dayton Audio AN25F-4 1" Soft Dome Neodymium Car Audio Tweeters
Nothing super fancy. I just wanted something a little better / more robust than the factory tweeters with the ability to handle lower frequencies without burning out. The reason for this is because I've limited myself to 8 channels of audio out of the 6x8 DSP, so I could only do 2 woofer, 2 tweeters, 2 rear fill woofers, and a subwoofer. The front door mid-tweeters had to go so I needed 1" tweeters that could cover their range too.
In the end, I utilized the space that the mid-tweeters used to occupy to mount the new Dayton tweeters. The A-pillar tweeter space was too small for the Daytons. I had to make new mounting brackets but they went in without a fuss and you can't even tell from the outside they are aftermarket.