If you look in the BMW Rider's Manual on page 126-127, it suggests replacing the parking light bulb with a wedge type bulb - W5W, 12 Volt, 5 Watts.
If you want to use the LED type bulb you want to make sure it is a Canbus Error Free type. This will help prevent an error from being thrown on your dash. The other thing to consider is the size, both width and length. If it is too wide it will not fit in the housing. If it is too long it will bump up against the lens. You also want to be careful about getting too many LED's on one board. Some types of LED's can get hot and could potentially melt the housing if not careful.
So, in answer to your question I would look at the "2825, 168, 194, W5W" bulb category and look for the Canbus Error Free type. I believe that the wedge bulb is about 3/8" diameter (10mm) and overall height is 1-1/16" (27mm). I have not purchased from this company before so, I cannot make a recommendation as to which one I would purchase. I hope that this is helpful.