I doubt the stock spoiler will create enough drag that it will reduce your gas milage.
I worked at a shop here in colorado called Checkpoint Racing and we built auto course cars and hill/rallye cars. unless your cars center of gravity is centemeters off the ground and your going very fast or a rallye car. Your stock spoiler is gonna be just for looks.
I worked at a shop here in colorado called Checkpoint Racing and we built auto course cars and hill/rallye cars. unless your cars center of gravity is centemeters off the ground and your going very fast or a rallye car. Your stock spoiler is gonna be just for looks.