I think Joe Black might have a good used transmission available soon

For engines, there are a few places out on the 'net that I've found, but the only one I can remember off the top of my head is Ebay. You might just check with Accurate Engines or Jasper to see what their cost is. Often, the engines they sell are actually better than brand-new due to updates to components over the years and the refining they do on the block.

Also try a search for "jdm engine" to find places selling used engines from Japan. Word has it that due to their vehicle inspection laws, a lot of good-running cars hit the scrap yard and are parted out to be sold to us gaijin. (http://en.wikipedia.org/wiki/Gaijin)