I wanted to decrease the length of travel during shifts in my M46.  I thought the easiest way to do this was to increase the lever arm length below the pivot on the stick.  I cut and welded in about 3/4" of material right below the pivot.  If you do this modification, make sure you mark the orientation of the lower connection point to the transmission actuator arm so it can be aligned later.  If you can add a dowel pin or something similar to pin along the long axis while welding would also help. If you want to add more than 3/4" of material, you will also need to bend the transmission actuator arm to clear the case.  While I was working on the linkages, I replaced all those wore out rubber grommets and nylon cups to keep the shifter more firmly located.

NOTE: Make sure you do a good welding job! My first try lasted about 2 years then broke at the weld while my wife was driving. Needless to say she was not happy.