SG wrote:
> Hello!
>
> I recently bought a Honda Civic Hybrid 2005 and its User Manual says
> that "Gasoline Grade should be 86 or higher", which means any grade
> above 86 which could be "Regular 87", or "Mid-Grade 89" or even
> "Premium 93" can be used, as I understand. If I use "93 Grade
> Gasoline", will it do any harm to the engine?

no

> What are the pluses and
> minuses in using the "93 Grade"?

+ = 0. - = $'s.

> What would you recommend and why?

why would you want to spend more money than you need to? this is an
economy car. run economy gas.

>
> I thank you for your time and will appreciate your advise.
>
> Regards,
> SG
>