I think the original flywheels are junk. They are cast iron. Once you've seen a billet steel flywheel, you wouldn't install anything else. To me, it looked like a piece of art that you could hang on your wall. They are absolutely beautiful.
If you buy one off ebay, you'll have to have it resurfaced. I think that runs about $80. So, 120 + 80 and for another 125, you can have a brand new flywheel. Hey, it's only money!
The other problem with buying one off ebay is they may not be able to resurface it depending on how bad it's cracked....they develop lots of little cracks...kind of amazing.