[TP2SS]

If this is a car you are going to continue to hardly ever drive, and hope it's worth something someday, I wouldn't touch it. Why bother spending the $$ for a car you barely drive? Plus, it WILL be worth more money down the road if it is unmodified. Even today it's worth more unmodified. The pool of buyers for modified cars is much smaller than the majority who look for "clean CarFaxes" and avoid cars that may have issues caused by mods. A GM CAI (with GM tune), and cosmetic stuff that can always be undone will not devalue it, so you could do those things and keep the OEM parts, but a tune or anything requiring a tune will devalue the car as any type of "collector" car later on. Just look at auction sales; "numbers matching" and "survivor" cars always go for more than even partially modified similar models.