better acceleration and most of the time smoother gear changes in the manual cars with no clunking. there's always a chance of increasing NVH but thats usually not a problem. ford put that noodle shaft in there to absorb the vibrations and noise they couldn't get rid of and it does a really good job doing what its supposed to do. if there is any issues in the drivetrain they may not even be noticed since the stock shaft hides it very well. one of my customers installed the shaft and had some vibrations. he noticed his wheels were wobbling so he swapped his 20" wheels for the stock ones and the vibration went away. the stock driveshaft masked the poorly machined wheels so well he couldn't feel them wobbling. one piece driveshafts don't hide things.