you are in luck now...
the radio is pricy. But look in the product info and it lists a harness and a bezel for 55 series tractors. Typed the number in the search bar on the top of the page and they came up. The harness is $27 bucks and the bezel is $15 bucks. You can buy those and pick up a pioneer or jvc or other radio at walmart for $75 bucks and be done. The harness is a plug and a bunch of colored wires. They usually have tags that say what each wire is. You just match them up to the same named wire on the radio and crimp them or solder them. Then unplug the old radio and plug the new one into the tractor wiring harness at the back of the radio and slide the new radio into the hole. May have to put the bezel on the radio then install it as one unit. Almost any kid that has installed a radio in a car can do this. Pretty easy..