On the cam, if it were me, I would stay in the 220°-224° range, around .525" lift and no narrower than 114° LSA. Many will think those specs are mild but remember, it's only 325 cubic inches. I have the GMPP LS Hot Cam in my 5.3 and I like it, but it can be a little choppy when its hot outside and you're in traffic or idling with the A/C on. It's 219/228 525/525 on a 112 LSA. My brother has the same cam in his 6.0 in his Camaro and it is better suited to the larger engine. The Hot Cam was really intended for the 5.7 LS1. I know running .600+ lift is the norm nowadays but I'm not comfortable with it. I have 65k miles on my cam swap in my Sierra and I get some piece of mind that the cam and valve spring combination was engineered by GM. I don't have to worry about changing valve springs because I'm out on the ragged edge with huge valve lift.