I use the regular carnuba wax on the seals with a separate applicator (the black gets on the applicator). Over time they will take on a nice low gloss luster and IMHO will last longer and not crack. Through years of doing this on all my vehicles, I have never had an issue and my seals look new. The one seal around the rearmost window is a different rubber material and has proven more resilient to waxing but with clever wiping skills it all looks consistent.

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2010 X5 3.0 X-drive Titanium Silver/Black
2018 Ford F-150 Platinum Crew
2010 528xi (His)
2017 M2 Manual (His)

Former Headaches:
2008 X5 RIP
2015 M235
2013 135is
2009 535xi Wagon (JUNK)
2007 530xi 6spd CPO Sport (Best Damn Car EVER)
2011 335xi M-sport Coupe 6spd (Sex on Wheels)
2010 550GT "CPO" (Junk)
2012 X5 35d "CPO" (More Junk)
2004 330i ZHP Sedan
2002 325xi Wagon
2000 323i Sedan
1998 M3 Sedan
1992 325i Sedan