The Z-1 is not synthesized. It can use the KO spektrum module.
The DX-3 has spektrum built in. It's not a JR radio, just uses the JR case.
I don't understand why everyone complains about new equipment. You should all be grateful that you have all the choices available to you. When I started racing we didn't have synthesized systems or multi model memory. 1fastdude can back me up on that. Be happy you have what you do and enjoy it, don't flame. A lack of features is another thing I don't get. Most drivers don't use the majority of them and wouldn't be able to feel the difference anyway. Most of the high end radios these days are great irregardless of which brand they are. I currently use a Futaba 3PK synth. I don't think it's any better or worse than the Helios, Z-1, M8, M11, R-1.
Point is, buy what you like and what feels best in your hand. Buy as much radio as you can afford. If you race a great deal and change between classes and channels, buy a radio that's synth or spektrum with multi model memory.
Futaba, O.S. Engines, Tornado Fuel, Schumacher Racing, SpeedPassion USA, Eggroll Inc., Desoto Racing, Vesselli Racing