I have heard a lot of people mention something similar and have had great success with differential bushing replacement with a polyurethane bushing. Also the rear upper control arm & mount.
Nice choice on the MGW. 5 turns is all I have tried mine at. I am very content with that setting. Until I got my mustang, I had never even set in a straight shift car that had the factory shifter. So driving my mustang felt like shifting a dump truck. Very happy with my MGW Flat Stick.
Glad to hear your success, the guys at Blowfish did a great job on this one. I was in the market for a T56 until I found this. Don't get me wrong, I would still love to have one. But, it's money that could go elsewhere until I break my 3650.
I wonder how many other people had bad experiences with the Blowfish bracket. There definitely are more vibrations as that is part of the design, it is intended to give more vibrations. The increase in vibrations was a very good trade for having confidence in shifting without being locked out...
For your concerns with twisting and missed shifts, give the Blowfish bracket a try. That thing paired with the MGW Flat Stick was $650 well spent for me. The whole point of having a mustang is to be able to have fun and take out everyone at your local Cars n' Coffee.