yeh -added drag changed the picture.
Also -the wheel pants add area - so no matter how streamlined - you have more surface area.
which equals more drag.
But as mentioned - you do look better with your pants on.
on a pylon racer - I would bet you couldn't tell any difference in lap time -pants on or off.
I still have a set of pylon pants and wheels - about 3/8" wide pants - over 1" in thick wheels.