look at it this way...people run rovers in south america and mexico and I really doubt your going to find a lot of premium pumps south of the border at least not in central and south america (I haven't seen many in Mexico)...the rover will be fine one way or another...just maintain it and if you run crappy gas, realize that you may wear things more.... What I can tell you with a reasonable amount of certainty....using midgrade gas is definitely not as ******* your rover as just a few hours of moderate off roading nothing tears up a vehicle faster than that, loosens up electrical, clogs filters, injectors, messes up steering, suspension, etc. and most of us do that, so a little less octane isnt going to make your rover vomit.