This is the bracket used with the first version of the SuperRacer AWD - this was used as a proof of concept and does not require any drilling.
The 3 additional steppers are just attached on the bottom of each columns.

The bracket has been designed to be printed on the edge (see 2nd print profile “Edge”) in order to maximize its strength.

Depending on the stepper used, the print area might need to be reduced to prevent the rods to hit the steppers.