I've always been a stickler for good quality gasoline, and I've had a few cars that will balk on anything less than 94 (but that's because I tuned them on 94).
With that, I run straight 87 from a reputable (amoco, shell, sunoco) dealer in the VX. This motor -with it's conservative timing- doesn't need the detonation prevention that high octane fuel provides. In fact, high octane fuel burns slower. I wonder how much of that fuel is still burning when it leaves your normally aspirated engine's cylinders?
Burn the best that you can afford, but best meaning quality of the fuel, not the rating. Steering clear of the Gulp n' Go Fillin' Station's pumps is better for your engine than running Ma and Pa's Super 93.