For E39 owners here, most would spend about $150 for the euro arm rest which is what I did a few months back. For the $150 you get the arm rest, the storage tray itself (which is available separately new for $25) and some hardware. I dont understand why they would 6x the price for the X5

I didnt want to pay $150 for a storage partition. So unless I find a good deal like racingbmwm3 mentioned, I decided to take out the tape holders, bore out the partition between the sliders and wrap it with vinyl tape so it doesnt scratch the contents I plan to put in there (like my phone, etc). I'll post a pic later today