I have a GS500 I was wondering which fuel would be the best for my bike? Is it worth paying extra for 98 octane premium? or should i just stick with regular unleaded 91 or just go in between with the 95? What bikes do people have and which fuel do you use? Have you been able to get more power or better milage from using 98 or 95 compared to the regular stuff(91)? Is there an negative side effects of using 98 or 95 in a bike like the gs500?