for the sake of discussion in Sleeper in Stock form.. (in Stock Form) meaning exterior is stock no signs of being moded a fast car that's why it's called a sleeper.. a Supra is not a sleeper? a corvette is not a sleeper? a ferrari even in it's Stock form is definitely not a sleeper! people know just by the looks that they are fast cars...much more a Volvo 850 T5R turbo! But for example
a chevy cavalier with an LS2 motor is a sleeper.. somebody has a 1980 datsun truck with an SR20DET is a sleeper..... for some reason when you drive a fast looking car people get so foamy and wanna race you...that's why these sleeper cars are out so the least you expect and booom... your volvo T5R 240hp is beaten by an old rusty 1968 volkswagen beetle with a 300hp subaru Sti turbo motor in it.. hahaha..