This is a remix from wantmys2000 strengthened extruder body. I added a filament tube holder and straightened the "flap" above the extruder stepper. The top screw hole area is redesigned so the part can be mounted with a M3x50 screw istead of a M3x60 which is sometimes hard to get.This modification shouldn't affect stiffness.
The spacer isn't modified, I only attached it to have all neccesary parts in one place.
as thick as you want to go
I used hexagon infill @ 25%
Use ABS or PETG (as I did). PLA will not survive the heat from the stepper.