I haven't done it in my X5 but I have done this in my other BMWs. If you do a search for this, you will see that its generally common practice and is easily done. Some chairs to require special pliers, so you may want to find a break down DIY for the E46/53 chairs.

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2001 BMW X5 3.0 5spd Sport
-aFe Intake
-E46 Sport seat retrofit with Heat
2007 Mini Cooper S 6spd