In SELECTseries 2 the template components for MX are driven by a specified cross section pss defined in MX.cfg. By default this is set to Roadway Designer section components.pss. You can redefine the styles the components use in the pss but you'll also need to update the itl if you change the component names.
With SELECTseries3 the template components are driven by civil feature definitions and element templates which makes CAD standards easier to achieve.
Regards
Ian