:help: I just bought this 2001 Durango R/T and found out after that it requires min. 91 octane. Why? I have read alot of things here and on other bulletin boards that say, all the 5.9L motors are the EXACT same. The only thing different is the exhaust in that it has a dynamax for the 5hp and 15 torque. I am thinking about taking it back and getting one with a 4.7L, but I got a great deal so if I could get some help in getting some better mpg and hp gains out of it with mods, PLEASE let me know what's best and the best order to get them. I ONLY get 11 mgp aver and would like to be up to 13 or 14 if that is possible since I have to drop premium fuel in it.