Spacers, been running them for 15 years now. On the e70 been running 20mm front and 35mm in the back. No issues with wheel bearings, ever. (What I thought was a bad front bearing turned out to be one tire going atrociously bad, cupping)

The German TUV clears spacer sets sold in Germany for general use. The TUV is quite conservative, if they perceived an issue with bearings when using spacers it would not be approved by them for general use.

On the other hand, when I bought my 4.8iS, the front wheel bearings were completely shot. I don't think it had ever seen spacers but I can't be sure. On my e53 I swapped the rear bearings coz they were getting noisy around 90 or 100k, fronts are the originals. Bit of a hit and miss if you ask me.

On a different note, I never understood lowering an SUV. First people purchase a 2 1/2 ton vehicle at a premium so they can have higher seating and a modicum of off-road ability, then diminish that by lowering it. If you want lower, wouldn't it make more sense to buy a 535xi wagon? Far superior comfort and handling as well as lower operating costs. (Stepping down from the soap box)


PS I swapped the wider flares on to my e70, there is nothing special about them. Mine was sport/active suspension with 19" wheels from the factory. The flares are an optical item, not a functional one. I have seen non-sport flares running OEM 20" and IIRC they don't stick out from the fenders.

__________________
2003 4.4i black ext./black int./black headliner (kid's runabout)
2014 535d X-drive, M package, silver/black interior

Sold but not forgotten:
2009 E70 35d, black ext./black int./black headliner (sold 2021)
2006 4.8iS Le Mans blue/cream int./black headliner, SOLD in 2012 sadly...

Other hardware:
2015 Cayenne S (wife's new DD and definitely wroooommmmm)
2016 Tundra 1794 edition crew cab, luxo hauler
2005 Tundra crew cab, weekend hauler. Sold after 150k very happy miles.