The electronics are very flexible. I have not heard of incompatibilities.
Those ebay parts are probably for:
[
reprap.org]
But people like these:
[
objects.reprap.org]
now.
-Sebastien, RepRap.org library gnome.
Remember, you're all RepRap developers (once you've joined the super-secret
developer mailing list), and the wiki, RepRap.org, [
reprap.org] is for everyone and everything!