Sorry to revive an old-ish thread, but I tried to install the BMS OCC on my 135i and failed miserably.
Got the cowl off fine, but couldn't for the life of me get those stupid clips off at either end of the stock hose. What's the trick to doing it? I was using small screwdrivers to wedge both clips up, then htrying to pull the tube off, but it wouldn't budge. In the end I had to give up as I ran out of light. It didn't help that I lost the screwdrivers down into the bottom of the engine bay 3 times and had to get the jacks out to retrieve them. Grrrr.