Well, if you do it right, you put it on your race car to make it go faster and only drive it at the race track. Otherwise, you do it to make your street car fa

Well, if you do it right, you put it on your race car to make it go faster and only drive it at the race track. Otherwise, you do it to make your street car faster (and maybe also pollute more), or worse, just generate a bunch of diesel soot to annoy other people with.