I was originally using the X10 motion sensor but it was unreliable and the signal was crappy - the security sensor works much better, so at least for me its a better fit. I may pick this back up again later but for now I'm not looking to make any more changes with it.
Fortunately the 433mhz sensors and the CM19E don't pose the same problem. TX/RX signal is excellent here. Assuming you are using a CM15a I've seen a few mods here that could improve your TX/RX range on your setup. They might be worth trying.