This transmission bracket (cross member) can be used for installation of a 6-speed transmission in a BMW E30. It should work with the Getrag 420G, ZF GS6-37DZ and ZF GS6-37BZ.
Weld all parts together and paint them.
The 6-speed transmission bracket for the E30 dimensions.
Use 4 square-headed M8X18 bolts (23711130250) to connect the bracket to the chassis.
Can you send the schematics as an dpx file?
Kind regards
You can download the STL file and convert it.
http://hobby.farit.ru/wp-content/uploads/2021/02/transbracket.stl