Some of these comparisons are probably a bit misleading vs. real world performance.
In the theory they might be true, but in practice the truth is probably something like a 20-40 percent performance advantage per clock for the '060.
An '040 does 1.1 instructions per clock whereas the '060 does 1.33. The 68060 also has some other acrhitectural advantages that cant really be measures in raw mips.
A 200% increase is possible on occasion, but its definately the exception rather than the rule.
Either way, even in a worst case scenario, @20% increase per mhz, plus the minimum available 20% clock increase its definately noticably faster.