Claytone

???

dkano

If you can only get one I would go with the intake and tuner first. Just seems like a good place to get your car "started" for other mods.

one_focused_svt

well of the 3 the gears and tune are kinda usless cuz you could go with just gears, and the exhaust will only help it sound better (maybe 6HP if your lucky) where as the intake and tune will boost ya at least 25/22 RWHP/TQ and is the only mod that will reall open the 4.6 up and let her rip, that and it looks more impressive when you pop the hood.