I think that would be incredibly goofy....why first of all? and secondly the engine would run incredibly poor....there this thing called 'back pressure'
that engines are designed around. Remove the back pressure and you a have a problem Houston. Ever stood next to a Cosworth Indycar when they fire it up cold? No back pressure because engine is designed to not have any back pressure...they won't idle and are obnoxiously loud....I see no benifit to that approach on a passenger car....