I'm selling my TW Magna, and want to throw the stock cd player back in. I've got an Alpine unit in atm.
It was installed by a professional when I bought the head unit, but I don't want to pay to get it removed.

What's the easiest way to take it out?

http://www.aussiemagna.com/forums/showthread.php?t=65249

read through that thread and it'll tell you how to remove the deck
depending on how they wired in the new deck the plug for the stock h/u may still be there
so all you do is cut the wire off from the aftermarket unit (where the wire meets the stock wire) then tape them up individually with electrical tape to stop them making contact with other wires, then wrap up all wires togther to neaten it up abit
other way is you'll have to chop off the aftermarket harness and resoilder on the stock one