Right now I have the stock, but I am going to switch to the twin. Just need to make sure I get the correct one.
The "correct" one is actually for a different application, we will customize the hardware kit to accommodate the NV4500 bracket (no extra charge).
Do yourself a favor, before you install the the bracket drill a 1/2" hole 1" toward the rear from the shifter mounting hole provided by AA.
The reason is the pivot point of the "J" type shifter need to be directly above the the shift-rail interfaces (in the neutral position) for the shifter to opperate correctly.
If you are going to rebuild the case, I would consider using "T" type shiftrails, they will allow you to have a spherical rod-end linkage and will allow you to mount the shifter farther forward using the original hole in the floor.