Yeah the stardard airbox flows plenty enough air, get a decent panel filter to replace the stardard paper one and then do the silicone inlet, they flow around 30 percent more air than the factory one, this will also be a lot more stealth if the plod lift your bonnet up

With the headers, if you go equal length then you will lose the rumble but unequal length headers will allow you to keep it, your choice, i'd be looking into maybe some Tomei or APS headers, they should be significantly harder to crack than their Hypertec counterparts

The list of mods youve got there sounds like it will be a good all around package easily capable of 300+ hp and some 12 second 1/4's

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