I just installed my LUX H8's on my '11 335i E90 and I love them! Installation was pretty easy and it only took me about 20 minutes for the entire job. I am very pleased with the outcome.
Here are a couple of tips to make your installation easier:
1) For both of my stock bulbs, their rubber o-ring came off and stayed attached to the bulb mount in the headlight, instead of coming off with the bulb. I had to reach inside the headlight and pull the o-ring out. For those of you having a difficult time installing the LUX bulbs, you might want to check and make sure the stock o-rings came off with your stock bulbs. If the stock o-ring is still stuck onto the bulb mount, the new LUX bulbs will be a tight fit, to say the least.
2) There seems to be plenty of room to work on the passenger side, but on the driver's side the power steering reservoir bracket makes it very cramped and I couldn't get my hand to contort enough to install the new LUX bulb. To give me more room, I removed the power steering reservoir bracket. It's only two 10mm nuts and a 10mm bolt and there is enough play in the hoses to move the bracket out of the way without disconnecting them. This made the job much easier.