I thought this might be a good place to gather information on common parts you've found with part numbers, prices, and where you found them. I understand that things like rear brake levers are likely an ebay or dealer item, but I don't like paying $20 shipped for a $6 seal.
For example:
The countershaft seal on my 2003 EC300 is 30 ID x 40 OD x 7 deep. It's an SKF 11600. I found it on Amazon for $6.21 shipped Prime ($20 shipped at the dealer):
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
I also found the o-rings for the countershaft are 25x2. You can get a package of 50 on Amazon for $9 shipped Prime ($15 shipped for only 2 at the dealer):
http://www.amazon.com/M1x2-5-Buna-N-...ds=25x2+o-ring
Anyone else have something to contribute? I'll continue to add items as I find them.