Why always premium gas on gsr integras?

Hi Eric I love the work you have done to your gsr. I also have a gsr. I used to own a 1997 Gsr that always said premium gas only. Today I own a 2000 gsr and it says the same thing. I hear people say premium is no different than the other. I want to know if this is true or not, so I can save money or keep using premium? Can you help me from gsr owner to another? Thank you for your time.