[aerohead]

I'm thinking that GM probably did a pretty good job with the underside of the Saturn and it's original airdam.If you go lower,you'll be increasing frontal area,actually increasing drag,and you run a good chance that it will strike the ground each time you go up or down a driveway.Some reports document that bellypans can show zero mpg improvement,some mpg improvement,or remarkable mpg improvement.There are no hard and fast rules on this one.If your going for really low drag,then I'd say do it,as future aftbody modifications will rely on the quality airflow only a full pan can provide.Carmakers aren't stupid and they can't waste shareholder money,and as you'll see more and more O.E.M. underside modifications to new cars,you definitely get the idea that they consider the underside something worth investing in .