This car is my daily commuter, so I opt to not have any deflectors or roof-racks just to decrease as much *drag* as possible for my 40-min highway commute.
If it was stop-n-go traffic for me, then it wouldn't matter, but the time I drive, I get to do about 60mph-80mph on the highway all the way to work (37 miles). If it even saves me a miniscule fraction of my fuel costs, I'm happy without any additional air disturbances.
Besides... I may be a minority on this topic, but I don't really like the look of deflectors, bras, spoilers, etc.
On an unrelated question (which I may start as new topic)... have any of you found a "sweet-spot" for fuel economy...? My last vehicle got its best efficiency at around 68mph-72mph. At that speed, my RPMs were just around 2k in a 6-cyl.