i just swapped a mini-me into my eg cx. i still have about a quarter tank of regular gas in it; i heard that you need to run a higher octane. sooooo...

what do i do about the spare gas in the tank? run the rest of it?

what octane should i use? it is a b7 block with a z6 head. i do not remember what head gasket though.

 

just fill the rest of the tank up with premium.