Originally Posted by Cal@Sonic MS
Important Note for 2011+ E9X M3 Owners
Due to BMW's anti-tuning algorithms, those with the latest BMW ECU software will require a basic (10AMP/20AMP) trickle battery charger that is capable of maintaining a minimum of 12.5V battery voltage. This is due to the fact that the read / write times are extended in order to bypass these "locked" ECUs.
so is that for 2011+ owners or for those who have the software update? confused a little there