What's the bet he buys a poopcharger?
OP
In seriousness. You won't get all that much performance out of the vq35de with bolt on stuff. You'll make it noisy, and it might feel faster, but it's not going to be a rocket. That being said, the order to do things is some form of plenum mod, be it a spacer, or plenum top, then exhaust and high flow cats. Leave the airbox the fk alone. Headers are ok, but expensive in cost and labour for the benefit. That's where to leave it unless you really want to plow some money into it.