Larger throttle body ?

I have a 2001 GT and i want to modify it. I am looking for advice on mods. Should i get a cold air kit or just K&N filter. I am thinking about a MAC cat back or just get 2 chamber flowmasters welded in. I know i wont get much power from either. Will i benefit from fitting a larger throttle body though, i read somewhere it's worth about 10 hp but i don't believe it on a stock motor.