I have SprintBooster on my cayenne and I love it! Everyone who has tried it does. It helps drastically when overtaking, and I did not notice a drastic change in gas milage. Especially with the V3, when driving through town, I switch it off, so gas milage is not affected.

As for air filters, I have an AP intake on my cayenne, and the difference in performance can definitely be felt. But I haven't heard of anyone changing their filters on an X5 d, so thats why they are a maybe.

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Current

2018 F85 X5 M - Individual

2012 E70 xDrive35d - 0km

2002 E53 4.6is - DINAN

Past

2002 E53 3.0d Sport

2007 E70 3.0sd

2008 E70 3.0is M-Sport

2008 E70 3.0d

2008 E70 X5 M

2011 E70 xDrive40d

2013 E70 xDrive40d