ya that is true, but N/A Fofos are sweet lolz. Ya biggest bang for buck is F/I. Look around the forums and read.
But whats your performance goal, i learned early that if you don't have a goal you will spend money like crazy and wont go very far. And do you have a Budget or any restrictions with money or anything. The More info you give us the better we can help you.
If you want to say N/A then i would say Header + Exhaust, Cams, Adjustable Cam Gears, Tune, etc
OH and welcome to the FF family!