OK cool. I hope you lobed it up really good.
I don't remember if the DDM shifter was made to allow the use of them or not. I really can't remember.. I would have to pull my shifter apart to look. which I will have to do because I did forget to put that piece of white insulation on.
while I do like the DDM short throw shifter it didn't do 2 things. it didn't shorten the actual height of the shifter, and it didn't shorten the throw enough to allow me to shift the car comfortably without having to lift my arm off the console. If you take the shifter knob off and look at the bottom of it you will see that the connection point actually comes out of the knob. This piece I shortened by 1/2 - 3\4" I didn't need any parts to do it, tools needed are a grinder, measuring tape, metal files, 80 and 120 grit sand paper, drill, drill bits, flat head screw drivers, either picks or snap ring pliers and a bunch of patience.
The patience is needed because that knob stem is hardened steel and it is going to take some time to grind it down so it's shorter. You also have to make some nylon spacers that are up inside the thing shorter as well, that's what the sand paper is for.
I still have to measure the height of the handle and also how far the throw is now and maybe get a comparison. I would be interested to know what the difference ended up being.
If you would be willing to you can measure it by putting the car in 3rd gear and resting a block of wood across the console so it is just touching the front of the shifter ball, then shift into either 2nd or 4th and do the same for the back. then measure between the 2 boards where the shifter makes contact with them. to measure the height put a level across the top of the shift knob and get it as close to level as possible, then measure from the level to the round chrome ring on the shifter boot, do this with the car in neutral and in a relaxed position.