Units that show WD1 on the label are rock hard against the voltage spike threat and any wireless interference. Units prior to those have a random 4 digit serial number after "INSP:" which may or may not have an internal copper shielding jacket. The ones with the jackets were better but not perfect but cannot be identified by serial. I should stress that just because someone has an earlier unit doesn't mean they will have problems. Its still a pretty rare thing and is highly dependent on ballast quality.
All of the Chinese sourced ballasts I was able to test sent voltage spikes into the cars electrical system as high as 300 volts (!!!) This is also repeatedly hitting every other computer in your system.
