Im using Civic SIR 99. Dati puro xtra unleaded lang pinapakarga ko pero I heard that mas maganda hatak ng XCS because of the higner octane number. So after madrain ng Xtra nagpafull tank ako ng XCS but nagkaroon ng different nginig orientation ung car. Medyo mas malakas at madalas siya.

IS ist because nanibago ang engine or i have other problems na? Balak ko bumalik sa Xtra after maubos ung XCS sa tank ko. Thanks