Originally Posted by fullmetaljacket

I had recent experience in this because I unfortunately bought a switchblade BMW key over at ebay thinking that it will work on my E53. Unfortunately, after I transferred all the electronic component of my old key to the switch blade, the X wouldn't crank up and start. Why??? because the transponder if installed on the switchblade key is too far from getting into the key housing cone for the X to recognize it! therefore I had to take all of the components back to the old key! ;(