The drivers were from the M5HPOWs. I've read you're explanations and I'm very happy to hear that there are good reasons as to why that experiment didn't go so well. It didn't make sense as the new drivers seemed much better, heavier stronger castings, they were bolted on (no self tapping screws), way more woofer excursion while playing, all aluminum woofer, and much beefier larger magnetics. Comparing the old driver to the new one is pretty neat, the new ones look incredibly better, like a comparing a rock to a polished stone. So I was surprised when my little experiment did't work out as I thought it would.
When you're spending well over 10K on speakers you need to know what you're buying! I get it, I know just enough to be dangerous, but the performance of the OW series on my particular walls caused concern. The EP600 & M50Ti's kept me listening.
