The intake comes off pretty easy actually, then you got lots of room to get to upper trans bolts, lift engine...

I still think the 6.1 is the easy way, if nothing else a lot of people are putting all the 6.1 guts in 5.7 blocks (including pistons) and I can tell you from experience it runs just fine, no CEL, stock tune.

On the later ones you can even put in a 6.4, I am currently runnin a 6.4 in my 2011 5.7 truck and you could never tell the difference under the hood unless you spot the BGE on the side of the block or in the computer as it's also stock tune. It adds typically around 10% fuel but it it is still within the allowable 25% before it would trigger a code.

The computers adapt pretty well to the bigger better engines, sure a tune would probably help butt it is still much better than the 5.7.