Does it matter what model 68000 I put in 2000?

[LaserBack]

if you use WHDload then you might consider the 68010. That will allow you to exit the game and go back to WB without rebooting. Very worth it.

yes but some old games don't works on the 68010 and in others it will cause problems or gfx corruption because VBR
sincerely I do not recommend a 68010 if the main purpose of the computer is to play games

[LaserBack]

btw,

you can found a 68000 12.5mhz on any megadrive and you can purchase it for a few bucks to dismantle and make experiments
and
if  my numbers are correct using the megadrive 68000 you will get a 75% speed boost on the A2000 or the A500

[LaserBack]

That's bull, as the processor runs @7+ MHz not depending whatever is written on it.

so it is clocked by the main 28 mhz crystal of the motherboard?
and what about a 14.x mhz 68000?