@Markus - the initial draw per headlight is similar to what the hallogen run onto constant. Luckily HID settles down to a mediocre 3.2amp 2secs after a cold-start. Having that low constant consumption is what's advantageous long term over the traditional hallogen - I'm guessing! For info; you rate at 30amp on the boxster headlight circuit so I wouldn't worry regardless of how you'd install two hid ballasts. Those combined drawing 9~10amps at cold starts
Think your cigar lighter is pulling something like 22amps lolll Go Go Boxsters forever!
@John - Thanks for your pm and the heads up on your thread
1. try to identify the ballast's POS + NEG and connect this directly onto a 12VDC source to see if they ignite. Not many ways to do this, either by opening the oem back cover of the headlight and un-shielding the ballast connector itself, or the easy way: use a pair of alligator clips and feed 12vdc to the corresponding headlight pins.
If the ballasts ignite on standalone current, my advice is to take the car to a garage equipped with car electrical testing tools. Unless of course you are confident with troubleshooting Porsche related electrical problems, then by all means. As mentioned by others, the first place to look is that ignition switch. They do have a few glitches those switches, not only one!. e.g. clean the circular connectors for one with alcohol or acetone.
Note: If it happens to be that mighty ignition switch being dead, double check around as I remember seeing that those were also introduced to Audi or Volks, or both maybe. Meaning the part is widely available and twice cheaper than the original porsche part.
let us know if you need help mate, luck there