I’ve written a few of these posts today where I fear someone on the forum will set me ablaze. LOL First, I’m a CA guy so I’m well adapted to paying too much for everything, including fuel. 91 Octane is 6.69 at the nearest chevron. Gotta love Costco But even that is nearing 6 now For 87.
Do the gas rams require 91 Octane? Are they considered high compression engines? If not, then burn what you feel comfortable burning, but I’ve always burnt what the manufacturer recommends.
91 Octane can be pressurized more before combustion vs. 87, so your truck will alter its timing electronically to prevent any pre-ignition or otherwise known as engine knock. Long term, lots of arguments if this will cause any noticeable damage since your timing can auto-adjust. If you don’t have a high compression engine, I don’t think it will ever make a difference.
Others might argue that premium has better detergents etc - I’d rather just dump in my own fuel additive so I know for sure it’s in there. Who really trusts big oil anyway.