Strange. I've never heard of them in all the years i've been into modding. I'm assuming they need to remove the ecu and bench flash it.
L7AS - any before and after dynos?
Current - 2013 N55 535xi Msport SAT
Retired - 2009 N54 335i Msport 6MT
Retired - 2000 M52TU 323i ASA Supercharged 5MT
More Photos of my car here