Thank you to all, I enjoy a lot ;-)

Tires are "standards" Dunlop 4x4 Sport Maxx (285/35ZR21 XL in front and Dunlop 325/30ZR21 XL in back), non run flat as they have problems to ship and they also are less comfortable and more expensive.
So I have invested in a "compressor repair kit" and have a good mobility insurance. I found it is a good compromise as I need it anyway for my 19" winter tires which don't exist in run flat.


Concerning the ride qualities, it's hard to say now as I drive quite slowly for the 2'000 first kilometers.
It is very precise to ride and even with the combination 21" and Sport suspensions form M Kit, it is still quite comfortable (more that E53 with Sport kit and 19").

Once I will reach 2'000 km, I will install chip tuning from Digitalchip announced with 320 HP and 640 Nm torque. Then I will be able to test my tires seriously :-D