First, congrats on the new Yukon--I thought they came standard with the 6.0 motor, but that is beside the point.
Our 04 Tahoe 5.3 has been very happy with whatever I have poured in or screwed on it--mainly Valvo Synpower & Puro 1's
No piston slap, start up rattle, ticks, or anything else-it's a good motor, although yours now has the alum block instead of the older design iron block
I do not think the LX exgine design is picky about anything!