Yeah, this morning I figured out that the special tools are not necessary to get the heads off. Right now there's a CIS 4.5 and a later 5.0L M117 in my yard of choice. So there is a definite difference between the EFI and later CIS heads? It would seem typical of Mercedes to have a differently machined head due to injector type. Though I'd prefer to get another set of heads I could swap with mine couldn't I also just harvest the unbent valves from the junkyard heads? Would a piston/valve collision cause other damage to the head castings or guides?