Light Drivers
Peach
Yoshi
Toad
Pros:
The light drivers are faster on grass.
They have better acceleration.
Cons:
Can be hit and slowed down easily by heavier drivers.

Normal Drivers
Mario
Luigi
Pros:
Can knock off Light weight drivers
Is able to hold off better when being hit by heavy drivers.
Cons:
Slow speed on grass
Bad luck on items
Does not have as good speed on grass.

Heavy Drivers
Wario
Donkey Kong
Bowser
Pros:
Can knock off all players when hit by them
Gets better items
Cons:
Slowest accelaration Cannot go on grass.