It was buried in another thread but I think this feature is probably significant enough to deserve its own thread.
More info on Lag/Rattle Fix (as well as other features): http://www.e90post.com/forums/showthread.php?t=183865
What it does:
1) Eliminates the wastegate rattle problem
2) Eliminates the boost lag issue with 29.2 cars
3) Improves boost response even in cars that don't have the lag issue
4) Eliminates the low RPM "jerkiness" that all these cars seem to have to some degree.
5) Gives back that low/mid RPM "slam" that everyone loved with old-school tunes.
It may even be a solution to male pattern baldness. More testing needs to be done on this though.