dumbest thing ever was probably when i had my 90 talon es, the thing was a piece of crap, but i bought a whole bunch of those performance stickers, like nos, holley sport compact, hooker headers, and whatever else, and stuck them on the side of the car and on the inside and everywhere. soooo rice. people would come up and be like "do you REALLY have headers on that? faaaaggggooottT"

on the car i have now, the dumbest thing i did was make a custom bov recirculation pipe. it didnt really help anything, plus it was in there so awkwardly, it eventually got replaced.