Pardon my ignorance but what is the McKenna system? Just looked at a thread noted above and I now understand that by McKenna you mean the system recently used on the Alex Job Racing GT3 RS's sponsored in part by McKenna. If this is correct, you might want to look at the thread I suggested above to CJV. I think you will find it interesting.

 

How manual transmissions work

How sequential gearboxes work

 

The clutch pedal for me provides the only form of exrcise for my left leg - LOL

 

I had an smg m3 and it was pefectly smooth and driveable on the street. You guys that didn't like it probably didn't spend as much time with it. It's like throwing a guy used to an automatic into a manul car and expecting him to be smooth. You have to learn the intricacies of it, once you do, it is very rewarding and easy to drive.