740iS - I think it's 12427568573 interference suppression strap. Mine (2012) is blatantly obvious sticking your head under the driver side right behind the rear wheel. Runs from muffler attach point to frame 12" away.
However with all the confusion above I am wondering if there might be more differences between the original and LCI iterations than we assume.

Same answer to BigBilly - on my 2012, if you slide under too near the rear diff and have a good look, there is a frame rail running L-R between muffler and diff. On the front side of this rail just driver side of center, this little unit is clipped. The wiring enters it from the end towards the rear wheel. Its a little bigger than a Bic lighter. It is labeled in German "REIFENDRUCK - KONTROLLE". There aren't many other electronics visible from this location and I saw it immediately. Which is why I am wondering if there are more differences between the early e70 and the LCIs.

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2012 e70 X5 50i MSport "The Boss" black on black *Well Optioned*