6.2Power

Been researching/reading about the 6.2 a bunch sinceI got the truck. The dealer filled it up with 87 octane. I have filled up 2 times since,once with 87 and the second time, i put in 91octane after reading that it requires it. So my question is...do I need to do the ECM fuse pull thing? Or does it realize the octane rating and change on it's own? And I will be running 91 from now on.

Just got a 2011 Silverado with a 6.2L. It is 4x4 ext. cab Black with black leather interior. 33,000 miles. I totally love it. Tons of power. The best mpg I have managed to get so far is 18.1 and that is with the cruise set at 55. Just wondering what is the first thing to get or have done to it to unleash the beast within? Programmer or cold air intake? Thanks in advance. Great forum guys!