I had a chance to replace my D1S bulbs over the weekend and took some pictures. Since there isn't any DIY for the E90 LCI on this topic, I'm going to post up the steps and hopefully it will be a useful resource.
If you're replacing the D1S bulbs in your garage, you're going to need the following tools.
1. Locate the jacking point on the side of your car and place the car jack into its position. The reason for not lifting the wheel fully off the floor is so that we can loosen the wheel nuts slightly and with it on the ground the wheel won't spin around. If you were to jack up the car fully and then try and loosen the wheel nuts, the wheel will most likely just keep turning around. Before you jack up your vehicle, you need to block the wheels. This prevents the car from rolling. You can use wood wedges, bricks, or you can buy metal wheel chocks from any auto parts store. Place the blocks on the wheels on the end of the car that isn't going to be raised up on the jack. If you don't have any wheel blocks with you, you should turn the wheels in toward the curb. That way, if the car does roll, it won't be able to roll into oncoming traffic.
2. Use the 18" ratchet with the 17mm socket to loosen your wheels nuts. Turn the tire iron clockwise until the lug nut gives way and loosens (do not pull out the nuts). If the lug nut refuses to budge you may need to step down on the tire iron, providing extra pressure. Repeat the same steps for the remaining nuts.
3. Now raise the car slowly with the jack until the wheel is off the floor. Completely unscrew the lug nuts and remove the wheel. Never jack up a car without jack stands. Jack stands are stands you put under the car to help support it. If you don't use them and the jack falls, you can damage your car and if you are under your car, you can be crushed to death.
4. Remove the 5 8mm screws and 1 10mm screw on the fender trim. Remove 7 8mm screws underneath the front bumper.
5. Slightly pull out the bumper panel and remove the fender trim.
6. Remove 4 T20 screws on the D1S cover.
7. When D1S bulb is exposed, locate the bracket, at the top push the tap down and slide it to the left then remove the D1S connector (make a note on how the cable is connected to the bulb).
8. Remove the OEM D1S and install your new D1S. Reverse the steps to complete the installation.
9. And the result....
WTF.... There's a screw left over.