Duane, Older remotes work fine with the XMD3 and the older XMD1 and 2 will work with the newer remotes except for the digital display style.
The XMD2 is the same as the 1 except it has C-Bus changer controls (not the style that will work with the IPOD) and dual RCA outs. The XMD3 has dual RCA out and C-Net control. Which will work with the ea125b clarion interface. I have heard the the interface is cumbersome at best so I still just use the AUX in from a IPOD cable made by Peripheral. check it out hope this helps. http://www.electronics-pluz.com/peipdotorcao.html
Also I've installed a ton of referbed XMD3 and had no problems. This is where I get them. http://www.bass-enterprises.com
They don't have any on the website but they do sell them. If I'm not mistaken they are less than 150 shipped. Good people to work with.