Assuming everything is stock the intakes wont need a bigger fuel pump or require adjusted fuel pressure! I waited till mine got noisey and then I upgraded!
A K&N filter with air box resonator removed or CAI should be next and then a new lower (at least) and upper intake manifold will get you the most bang for your buck. Then a bigger MAF will help also. Gears can be done at anytime for extra SOP excitement (index the driveshaft both front and rear after gear swap)! And don't forget about pullies.
After this it gets more expensive.....cams, heads, RR, upgraded ignition system and injectors. More cooling will be needed also!