I agree with what BobT said,
it depending on your budget, here's my recommendations that get more expensive as they go up!
Gears, do gears first, 410's if your staying NA, 373 if your adding NOS or boost.
PI intake swap and or tune -- around 30 HP
Nitrous -- about 100 HP on the Juice.
PI Headswap -- around 80 HP
Blower -- around 130 HP, and get's better if you have heads/intake to go with it.
The rest is just fluf, except exhaust, because we just love the sound!
Hope that helps.