Definitely do get a quote from an Independent shop... these items are easy enough to do (mostly DIY type of work if you have the tools and the patience/time/place to do them), so definitely any good BMW shop should be able to do these with no worries.

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Currently driving: 2011 E70 x35i , 2011 E90 335d
Previous BMWs: 2007 E90 328i , 2005 E53 3.0i, 2011 F10 535i (6spd manual)