I have heard the same about the Keisler unit. I had a bunch of problems with the first one...it wouldn't keep the transmission in 6th gear. I called Keisler, and they disassembled the transmission, and replaced the kit which now shifts very well. They told me that the first ones they made (which I had one of) had some issues that were corrected. Mine shifts great

You can't use a pro 5.0 shifter in the front hole because you have to cut add a piece into the center of the transmission rail for the shifter to fit in to.

90'rado
I would be interested in any pictures you might have of your shifter.
Wish I had a 14 bolt. That is what these trucks should have behind the manual transmission, and I think you will love the 4.88.