Neil, no, I meant that 472 works with the x, because I'm pretty confident that it does! I have a car sat here with a 472 in it, and its owner uses a x radio! I could dig my old X out and bind it up just to confirm, but I really can't be bothered.
The 4x2 receivers allow setting of the Sanwa esc' from the radio. Although that feature is z specific, so no benefit (other than size vs 451) with an X radio.
The 471 is FHSS4, it says so on the link you helpfully put up
