The Vararam is supposed to be the one that shows the most performance for our trucks, followed by the S&B Cold Air Intake... People choose S&B over the Vararam sometimes because of design, meaning for people that live in climates with a lot of snow / sleet etc, the sealed design of the S&B is probably a bit safer... the S&B fit and finish is also better...
As mentioned, the DiabloSport tuners are the tuner of choice for these trucks... You could purchase one from Moe's Performance or HemiFeverTuning and get custom tuning options from HemiFever (or Jay Green etc) and that should really wake the truck up...
Then of course, you'll want to add exhaust, maybe a ported throttle body, maybe even long tube headers... and on and on...