[stefano7171]

Since March 2007 production, BMW 335ì, 335d, 130ì are equipped with an electronic differential lock.
The same system will be fitted to the 135ì.
Essentially, it is not a mechanical LSD, but the effect is similar. It is reported to be as an LSD, just a tad slower and easier to manage.
It is possible to "drift" with it, something that was not feasible with pre march production cars.
The differential itself is welded, not bolted (that is why Quaife is asking for more money to modify into real LSD post march production cars) and the DTC has a revised logic. In fact, with all controls OFF (press button for 5 secs...), the DTC intervenes when a tyre (normally the one on the inside of the curve) starts spinning and uses the breaks to slow it, transferring torque to the non spinning wheel.
The strange thing is that BMW has advertised this system six months after introducing it into production.
An EDL will be dismounted in a few days in Italy to find out if the internal mechanics differ...and the findings will be posted on the Italian forum.
Apparently it is not just "a software" so pre-march production cars can not be updated to EDL with a simple software upgrade......