Forget the FIT mods, you don't have an L67 and all the non-sc mods are for VT onwards.
The Type S CAI won't fit (not easily at least) as it's designed for the VT+ engine bay which has it oriented the other way.
Get a good stainless steel 2.5" exhaust, it will give you a sweet sweet note and a bit more pickup. $600+ for stainless with tip
No need for a "hi-flow" air filter, just buy a new clean paper one these flow 99% as well and let through less junk, plus you don't need to clean them. $5 for a paper filter.
Skip the SS reductions CAI, the holden one for the supercharged VS is just as good and all the bits (including the modified bottom half) goes for $70 or so from holden spare parts.
Extractors you'll hear two things about, some say not worth it for NA but some say it is, however if you do plan to get it blown down the road then it's a must-have. varies depening on brand, budget $500 or so for something half decent.
Rockers are an excellent upgrade, improve power all through the range with no significant economy decrease, simply makes the engine run more efficiently. $800 for a set + install.
If you do go down this road, look at a custom tune. If you can get to a Kalmaker tuner this will get the best result (assuming a good tuner) as it uses the factory ecu and can utilise all the sensors etc to run it to the max. BCT have this on special for $600 but are in vic, local tuners may be more, budget $800 or so for a good tune. If you go aftermarket you'll have to get a piggyback installed which adds to the initial cost, but subsequent re-tunes would probably be cheaper.