Which petrol to use in GMC Envoy 2008?

[SyedAftabA]

I have just bought a new GMC Envoy. We have two types of petrol in my country i.e. 91 octane and 95 octane. Some one has told me to use 91 octane petrol as he says, the american cars are not designed for 95 octane. Please let me know the following:
1. Which petrol to use for this 6 cylinder vehicle?

2. Is the fuel efficiency and pick up better with 95 octane.

[edc]

95 it will save you gas because it will burn better and since you have a big block it will work great dont cheap out on a new vehicle

[edc]

95 it will save you gas because it will burn better and since you have a big block it will work great dont cheap out on a new vehicle