It's a shame the real deal or good copies are so expensive, those welloem HID kits that were mentioned were nearly 300 dollars.
Now I'd rather invest a few quid in foil to resolve the issues of a 60 quid kit.
So how comes OEM ballasts don't cause ABS issues? afterall there mounted in the same place that most of us are putting them.
You can get interference free HID kits for 100 quid. No need to spend 200 or 300...
Not everybody is so lucky & can use the Aluminum foil trick.
In some cases it doesn't solve the problem completely (depending of the HID you have, some give stronger interferences)
In other cases like the Audi A3, the Aluminum foil trick is not safe.
for the A4 we are just trying to avoid a light in the dashboard.
for the A3, only with 1 time exposure to the interference the wiper motor will blow away.
It can take 1 day or 1 year, but eventually it will happen & the cost of the repair is quite high.
OEM Ballast can cause interference too.
It all depends on quality & technology they use.
The most modern ballast the most advanced technology & the lower the interference.
Older HID ballast may produce also interference. (saw it by myself)