I decided to start a new thread, so that this information wouldn't get lost in the "Thanks!!!" thread. Fast Italian asked how you can polish the ZF and keep it that way, and made me smile with his story of his efforts.
Mine isn't polished, per se, but I read a great tip a few years ago that is worth repeating. If you don't want to spend the literally thousands of dollars it costs to do this right, you can do it "almost right" for about $3.
Go to a hobby shop and buy yourself a tube of a product called "Run 'n Buff". The original wax metallic finish. It's supposed to be used for picture frames or wood stuff, to give is a nice silvery color. I can send you a photo if you'd like to see what the tube looks like - I have one hear.
Clean up the ZF and rub this stuff on with your fingers. It is basically the same silver color as a ZF and covers well. It dries quickly and can be buffed for more shine. It appears to last for a long time (I applied mine 2 years ago and it still looks really clean). If you are preparing for Pebble Beach, the experts will be able to tell the difference, but 95% of those won't, and it really helps restore a uniform, clean, and shiny surface to your ZF.
Try it and see what you think. It'll cost you all of $3 and an hour, which makes it a cheap experiment. I drive my car an awful lot so I'm not interested in plating or polishing my transaxle, but this product made it look like I had a brand new ZF in my engine bay...
Hope this helps.