99.9999999% with Shell V-Power. I had to fill up recently with Caltex's Vortex 98 and it too was good. I have only used the top of the line premium fuel ever since my first BMW, an E36 320i back in 1992.
Even works a treat in my wife's C180k. Longer distance driving compared to the next level of fuel down. Supposedly a cleaner burning fuel, so the extra spend at the pump results in more kms on the road.
328i M-Sport, Estoril Blue, Carbon XP 35 Tint, front heated seats, black Dakota, Sports Suspension, Anthracite Headliner, HUD, Pro Nav, Sunroof, hk 600w, Bi-Xenon, 19" 403M wheels, Reversing Camera, DAB+, Xenon, BT Ext Connect.