Anyone whom has overclocked any Amiga '040, 060 or PPC card obviously has not yet experienced - as I have- the sudden death of their Amiga.
The guys who built the card "KNOW" that the CPUs can go faster but maybew thye were constrained by cost into using parts that fit into the chain that WILL NOT stand the strain of overclocking.
I know, I got my formerly overclocked CS MkII back from amiga.fr last year. It had run happily at 60Mhz for four years and then ... just died.
A standard '060 (whichever) that operates within it's design parameters is much faster than a stock Amiga and will give you lots of satisfaction for a few more years yet.
Don't overclock.