Corsa = awesome,
Shorty headers i'm sure some will disagree ( Ceramic Coated)
3.73 good idea
true intake not just a drop in i run an AEM brute force
Nelson tune for whatever octane you want to run obviously 93 = best gains
underdrive pulleys
low resistance plug wires if running headers get high heat resistant also
e-fans will help performance and mileage i think
shaner ported & polished throttle body great mod for stockish vehicles and highly modded as well
remove cats if possible in your area and have tuner delete rear o2
Just some stuff i thought would help out

Good Luck