could anyone tell me how the best way to remove the factory stereo in a 271? Can you remove any of the panels?

I did get the grey colored panel on the top off, but do any of the others come off?

Pop off the face plate and there should be a couple of screws holding the unit to a frame (just like a car stereo).

If you have a closer picture it would be easier to tell what you have to do...

There's usually some kind of clip system on each side that holds it in. Pop off the trim ring around the faceplate. The removal tools will slide in on each side, but there are different style tools and clips on different brands. Yyou can try getting it out with a very thin screwdriver or butter knife. Grab one side of the stereo and slide the screwdriver/knife carefully in at the side and see if that releases it. If not, see if you could find or borrow a removal tool from a car stereo shop.