Hi.
I used this kit on my mk2 zt with halogen projectors.
https://www.hids-direct.co.uk/h7-35w...onversion-kit/
No issues at all. No canbus bulb errors.
I didn't use a relay harness because of the reason you said. It only takes its power from one lamp so bulb out warning would happen.
Do your headlights flicker or go off intermittently?
Have read about this fault before on hid planet forum and it was a bulb shorting in the lamp unit causing the engine to cut out.
Worth a look..
I can say the kit I got from the above link works bang on. Nice bunch to deal with as well.