I try...
I have kept pretty much everything thus far, sans' OEM air-filter. My reasoning is in-case I acquire a different NSX in the future and sale my current, I can easily swap the aftermarket components that I wish to install on the recently purchased NSX (ie. my JGTC Parallel exhaust, NA C30a Mugen NSX-R ECU), Philips HID's, aux. input converter & mp3 device, powered-subwoofers, V1 hardwire/stealth install, CF shift-boot & titanium shift knob, and other minor components) . [reversible-mod's... not body-work, susp., etc.]
The NSX being a niche' market automobile as-is, marketing a 'clean' stock car would be more helpful towards a quick sale than a particular car that has been modified or personalized along a certain theme. Matching a NSX buyer w/ a buyer who wants mods' can be time-consuming.