@ boinger
CS MKIII is just an 060 or 040 CPU card only.
CSPPC has an 060 or an 040 CPU as well as a PPC CPU.
Both the CSMKIII & the CSPPC use the very same PCB board. It's just the PPC has more Juicy Bits on it & will run OS4.0 Classic, where the CS MKIII will not because it has no PPC CPU!
Yes, the one red is selling is worth bidding on. Be warned though, these cards are rarer than rocking horse sh!t. The final price could do some serious damage to your wallet. :-o
The CS MKIII's are prone to cracking their CPU Joints with age & mis-handling. I was lucky enough to have one repaired for this very problem after it arrived DOA.
CS MKIII's are geting near twice the Speed on RAM access due to Dual Channel Access. (64 bits instead of 32 bits) This means a 16Mb Ram transfer gets split into 2 x 8Mb chunks accross 2 x 72 pin Simms @ the same time instead of chugging the whole 16Mb into one Simm. It's deeper than this really, but keeps it understandable. ;-)
CS MKIII's also have UW SCSI III as standard.
The previous CS MKII's & Mk I's have an optional SCSI controller & are not always available with the main PCB. They just plug onto their repective cards. MK I SCSI controllers can not be used on CS MKII's & vice-versa!
Hope that clarifys all your concerns & Good luck! :-)