I don't get this. If your shifting is jerky, you are just poor at operating the clutch and need some practice. I see these posts all the time. When I first got my E92 I was a little sketchy on shifting and it was a little jerky. It took a couple weeks before I could shift smooth like an automatic. No pauses between shifts when driving slow. When shifting fast, you should be able to screech the tires with no lag in acceleration.
Jet Black E92 ///M3 | Bone Stock