Pretty sure those spec was just an typo when someone mistakenly meshed up the spec of SE215 (which Aonic 215 comes with by default) with that of RMCE-TW1. For once, the adapter itself can't have sensitivity rating or even a driver.
Shure never released any particular useful info regarding RMCE-TW1's output power or output impedance, nor did I ever see any measurement of them. However, judging from the fact that it supports aptX, we know it is a Qualcomm chip. From its release time, I'll venture a guess it is likely going to be QCC3020 like almost everyone else is using. The small size of the adapter also suggests that it won't likely have an separated amp chip as there isn't enough space (*and also that fact that Shure doesn't bother telling us about it, nor is Shure ever paid attention to output power, etc). So in all likeliness, this particular Shure adapter should have mostly the same level of hardware as TRN BT20s - On that assumption, output impedance should be fairly low (QCC3020 normal output impedance is sub-1 ohm, unless Shure intentionally added output resistors). Output power is probably just a few mW. None of this is particularly bad information, except perhaps when you considered that the Shure adapter itself is selling for $180 or so while BT20s can be had for $30. For QCC3020 based hardware without any fancy add-on, I think the more reasonable price for a big brand name product should be around $100 or so.
Plus, even after all these months after announcing the product, it is not available in Singapore, where I am currently.. So even if we somehow order and get it from US, there will be no warranty on this product. That is worrisome on such an expensive product. Maybe the prices will come down during black friday or other upcoming holiday period. In the meantime, other products from other brands may also be available in the next few months.. So can wait a tad longer.. But honestly, been waiting for too long for a product like this.. cant wait for much longer! 
