That 5.3 flex fuel motor is somewhat to be desired and honestly most likely it could use some valve train work and that's about all it needs. I would suggest selling that motor to fund your 6.0/80e swap. Your right about the 60e being trash. If you are great with software and have good automotive knowledge then hptuners/efilive would be a good investment. Having a base model does have the perk of being very lightweight compared to other models meaning going fast will be a little easier. Have fun and lets see sme pics. Also I know I have seen some GM vehicles where simply adding a turn signal lever equipped with cruise is plug and play without making any other changes.