The MPC106 really doesn't take to overclocking (especially since 83MHz is about a 30% upclock), so you're likely stuck at 66MHz. I don't know why the upgrade providers never used the 83MHz variants. You'd figure if Sonnet or Newer could offer any sort of bump over the competition they would. I had ideas of desoldering and replacing one of the original 250 or 292MHz processors with a 500MHz version, but I would also likely have to source faster L2 cache chips (if I wanted to run it faster than 5:1, at least) and the 83MHz cards only had the BGA-style L2 cache chips, so that may prove difficult.
As far as the Lombard goes, the 333MHz version really has nothing on your overclocked unit except faster video and built-in USB. You had to buy the 400MHz model to get the built-in DVD decoder hardware, though the 333 could use the WS's DVD decoder card. Personally I generally dismiss the Lombard as a sad speed-bump on the road to Pismo, though honestly I'd prefer the WS/PDQ over any of them because the WS had a double drive bay, floppy support, SCSI, two CardBus slots (for adding USB (including 2.0 support under 10.2.6+), FW, and 802.11g wifi), and a better keyboard. With a processor upgrade, the WS could be faster than a stock Pismo/500 anyway. The only real reasons to get a Pismo are for the better video system and faster memory bus. I guess they're lighter, too, if you're not up to hefting a fully loaded 14" WS.
