For a setup like that, a canned tune is gonna suck the D...hard.
Rockers are boring, but if you don't want to cam it, I understand.
As for the GenV and LIM, I've actually got a GenV and matching ported LIM to go with it...both in great shape. Shoot me a PM if you want it on the cheap.
TB, I'd go ported stocker. Especially if you go rockers, it's gonna flow just fine. If you do anything over 1.80:1 ratio rockers and 6k RPM shift points, you'll want to change the springs, yes. Which means probably going with LS6's. Easy, they work, and they're cheap. Tried and true. Pushrods? Meh. That's up to you. I got Intense O/R pushrods when I built my motor.
