I sent few questions to the seller of the stuff (link in first post by OP) and following is the answer.
Hi, thanks for your enquiry. To answer your questions:
1- Are these straight fit to E90? (no wiring alteration)
No wiring modifications are required.
2- Also what sort of bulbs should be used with halo rings?
3- Are those like parking side lamps or different bulb?
4- Are those two for each halo ring or one should lit both?
Halo rings have non user-replaceable white LED rings.
5- Do they become misty or foggy after use?
Condensation can occur in any lights, even original equipment units. It occurs due to moisture in the air inside the light and not because of any fault with the lights themselves. It is more common in cold wet weather. Condensation is not accepted as a valid reason for a warranty return by lighting manufacturers.