Why stick a 68010 in a Genesis? For fun! (And the minor speed boost.) Performance gains in 2D games are minimal, but 3D games got a decent boost. In 3D games, a 10MHZ 68010 has roughly the performance of a 12MHZ 68000.
The mod work wasn't too hard, just time consuming. I had to desolder the entire CPU from the Genesis, and replace the CPU with a 64 pin DIP socket. After that, you can slot in your 68010, or a different 68k. I piggy backed an oscillator on to my 68010. The oscillator is also socketed and draws power and ground from the CPU pins.Here is a video showing some games running on a 68010.
Below are some images, performance info, and compatibility info.
68000 (7.67MHZ) - 5220
68000 (10MHZ) - 6756
68010 (10MHZ) - 7104
It's hard to measure performance here, but Hard Drivin on a stock 68010 is almost as fast as on a 10MHZ overclocked 68000. Video of Hard Drivin on a 10MHZ 68010
68000 - 15 FPS
68010 - 15-16 FPS
68000 17-18 FPS (mostly 17)
68010 17-18 FPS (mostly 18)
32x - works!
Game Genie - works!
SEGA CD - works!
SVP (virtua racing) - works!
Adventures of Batman and Robin - random freezes.
Bugs Bunny in double trouble - black screen on start up.
Comix Zone - black screen on start up.
Elemental Master - black screen before opening cutscene.
Knuckles' Chaotix - freezes on loading, saving, and finishing the first stage.
Lawnmower man - freezes after initial 3D stage.
Popful Mail (SEGA CD) - black screen on start up
Red Zone - freezes when starting game.
Sol Feace (SEGA CD & Genesis versions) - freezes on title screen
Sonic 3 - freezes upon loading a stage.
Sonic and Knuckles - resets on SEGA screen.
Sub Terrania - freezes after SEGA screen (I'm working on a patch).
Thunder Force IV (AKA lightening force) - black screen on start up
Titan Overdrive (demo) - freezs after checkered floor part