I don't think tear gas will make it run any better, and the driver may not be able to see the road clearly, which sounds dangerous. On the other hand, using Top Tier gas isn't a bad idea.

Top Tier is in no way a quality standard, though. It is targeted solely at reducing deposit formation, a problem that hasn't really been evident for some years now.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue