Wanna speed up my 5.3L Yukon
I got spoiled to fast v8’s with my very first car and each latter vehicle. Fast forward, I’m driving a 2016 Yukon slt, “mommy mobile” with 5.3. I thought about having it tuned. The eco part drives me crazy. I have yet (knock on wood) to have any problems.
Realize that you got a 7 years old big truck. You don't have issues with it, so as @Daywalker said, do not mess with it.
If you want something fast, you probably better off buying something smaller and lighter.
Go on a vehicle weight reduction program. Tear out all interior items except for the driver's seat.
Something like this should do the trick, with the bonus that it doesn't require monkeying around with your engine: