I changed to Osram Nightbreaker Plus on my Audi last summer and they're a great improvement, so much so I ordered some for the BM. They turned up a day after the BM died and was carted off the dealer... so haven't fitted them to the BM yet.
Fitment for mine is under the wheel arch, but I've already taken one out to check iot as the gas has gone so its quite dim compared to the other. I'll be fitting them as soon as I get the car back and will let you know what I think.
As for my Audi, before they were yellowish and not as bright as the BM, now they are whiter, brighter and have a very subtle glint of blue in the middle, nothing like the boy-racer nasty blue-shite they seem to favour but oh-so Xenon-ish, 95% white with 5% blue, spot on IMO so hoping for the very same improvement on the BM
2014  M135i, 3dr, MG, Auto, SP, CP, HS, HK and FBP
2011  Abarth 500, Funk White, Leather, H&R
2007  320d M-Sport Touring
Pre 2007 - GT TDI 4MO, Mk4 R32, A3 TQ, A3T, Cupra R and on and on and on.....