Horsepower

I Know this isnt a repair question but I have no luck anywhere else. I have a toyota celica with lots of cool lights I find at wal mart and autozone and stuff and people keep laffing and tellin me to add horsepower by getting stickers and I wanna know if this is true, it might be true cuz u see the nascar cars's have stickers all over em and if it works what stickers do I need