Agreed. (eBay kits are trash.) They will work decent for a few weeks, but after that, the ballasts will get moisture in them and fail, the bulbs will die, etc and you'll get in one night and try to drive home and wonder why your headlights are dead.
You say if you just use lowbeam bulbs the pattern is better? Are you referring to the "non" Bi-Xenon kits? Its the same thing. Aim them lower, that will helo a little but, but TONS of that light is still scattered up and blinding people.
A true foglight wouldnt blind people

I have 6000k in my fogs, BUT I ONLY TURN THEM ON when im on the long backroads that have no lights, and when theres no cars coming. I would dare drive with my foglights on when theres traffic. HID in our foglights are worse than the headlights themselves.