I have heard that the bolts for 2.1 l con rods are not the greatest, and should be replaced on a rebuild with 1.9 l bolts. I don't have any 1.9 l engines around I could steal them out of, and would also worry about re-using "tired" bolts in an upgraded rebuild, anyway.
  Does any body have any suggestions? I haven't had much luck on my own, but I also have no idea what other bolts may be a usable substitute.