Cam is a VERY serious mod that pretty much gets rid of displacement on demand which means you'd lose some highway gas mileage.

I'm not sure what cams people run in those engines, you'd have to search google because I'm fairly certain the LS4 crowd doesnt hang around here.

Theres a headers group buy for it I suggest you get on ASAP.

Transmissions

Scroll down to the one at the bottom for $1650, thats the one you want. Possibly an upgrade or two.