Does the 2004 engine perform slightly better than the 2003?

[Centerfire]

My 2003 still gets 10.4.. Got a heavy foot. didn't care what the mileage was before I bought.. I do not care now after 8K miles.. still get 10.4mpg.. WOuldn't even know this if the H2 didn't keep track.. I just go to station when its thirsty and move on.. Like my daughter says its a "coke machine with wheels, not a sports car"..
ALl I know is its cool and mileage is not a issue in INdy with gas back down to 140 a gallon.. Besides I am use to feeding my older custom suburban that gets under 9 mpg ( I think). and it holds 45 gallons and I have to use prem + booster to feed the supercharger. So the H2 mileage ain't no big thing.

Mike