In my experience, you wont get enough gain out of the ZP3 with that cart. My MM, with more than twice that, really benefited from having a pre after the ZP3. My MC, with a ZMC1, gives me about 5 or 6 times what you would get out of the ZP3.
By my calculations, you get 1/2 volt out of the ZP3 with a 5mV cart. Without a pre, I don't think you can take advantage of full power in any amp that requires more than 1/2 volt, which includes all of the Decware amps.
Anyone, ... please correct me if I have this wrong!