The CS MK3 can have an oscillator put in the middle oscillator slot (add a socket) to run the 68060 and the original oscillator will clock the SCSI and Zorro bus. A very small jumper has to be changed. The Amiga Center in France can do it for you. You still need a 68060 and memory that can tolerate whatever speed you want to run. Here is the writeup you need...
http://members.iinet.net.au/~davem2/overclock/csppc.htmlGet your very overclockable (90MHz+) and rare 68060 from here...
http://www.amiga.org/forums/showthread.php?t=32783And then hope with all the money invested your CS doesn't crap out on you like mine did.