Even the stock replacement bushings will still have some play in them. The are designed to be that way. I tightened up my shifter by installing a B&M short shifter, Symborski shifter plate bushings, and a shorter shift knob. After all that, the only place for slack in the shifter was at the linkage bushing on top of the tranny. There are two, one for the forward / back movement of the shifter, and one for the side to side movement. The play you need to worry about is in the forward / backward movement.

Remove the linkage arm and look at the bushing. You will see that the bushing has two grooves cut into it that allow movement in the linkage before the arm will move. I filled these grooves with JB Weld. After that there was zero play in the shifter. It goes right into gear, no guessing. Just make sure you center the bushing in the linkage to get the JB weld in both grooves (one on either side). I wish I had pictures.... but once you look at it you will see how to fill it.

-Jared
96 GS
Melbourne, FL