...mine is also officially on order and due in a few days, cant wait. As for the US only models its not the TX but the RX that will be different. Thats not to say that the current RX-451 shipped with the first batch of M11x's wont work in the US. Its the TX that has the new FHSS-3 format installed not the RX. The antenna on the RX is also noticeably longer than the previous version of the M11. This is to ensure optimum communication of data.