Quite frankly, the performance gain by either of these methods probably isn't worth even the postage paid for the items.
1. Replace a 7mhz 68000 with a 7mhz 68010 and you get:
- negligible speed improvement (only measurable with benchmarks)
- reduced compatibility with games
2. Replace a 7mhz 68000 with a 14mhz 68000 WITHOUT adding a new faster memory subsystem and you get:
- negligible speed improvement (5-10%)
- you also need to build circuitry to do this
#1 just breaks compatibility, #2 just doesn't make sense without faster memory. I owned a CMI Processor Accelerator, which is just a piggybacked 14mhz 68000. 5-10% speedup. No lie.