sorry, but octane doesn't mean anything unless you are driving to the max of the engine capacity. any octane will be just fine unless you are redlining the engine....it would matter then but who amoungst us redlines the engine? I don't, 87 vs 91? come on, that's trivial and the computer would compensate for that anyway....that's all tripe.....It's to make peope who drive BMWs and Mercedes and so forth think they have this really high performance engine that must have to have this fuel to make it perform up to these standards...pure hogwash....believe me, pure marketing. Not only that, but German octane is different than US ratings.....