Is it ok to use regular unleaded in a 2001 RL?

You can run it with 87 octane (regular fuel), but if you want to have the best MPG you can get and all of the original 210 hp your 3.5l¸can deliver, you must use 91 octane or higher (super).

Thanks

I have a friend, who has a friend that works for the dept. of energy in the division that deals with the grading of auto fuels. According to this friend the grading of fuel is more for the oil companies benefit than it is for the customer. My friend has had many different high end very expensive sports cars as well as very expensive luxury sedans, i.e. Audi, Mercedes, Italian sports cars ($100,000++) etc.. His friend told him he could definately use regular fuel over the premium with absolutely no negative side effects since there is no difference in the fuels. The grading system is bogus according to her. I have been using regular unleaded in my 2003 RL ever since with no loss of power or suffing of poor fuel economy.