[Little General]

I have an 08 and can't get much better than 14.5 at 55mph on flat road. The lie o meter says 13 most of the time. I tried to get a K&N filter, don't make for 08 and exhaust system, none I have found. My brother in law ia an engineer for Wix Filters and says the filters for 03-07 H2 and 08 are the same, just different numbers. Also, he did a flow test on Donaldson Filter and K&N for H2 and said the donaldson did just as well. He advised me not to waste my money on just the filter but can't commet on a full cold air system. I also thought about a 50 series Flowmaster Muffler. The pipe size looks plenty large. About E-85, I wonder if Hummer will offer a reprogram to 08 to allow E-85 use.