The Hed bars are meant to mount your computer on the small front crossbar in front of the stem mount. That being said, computers with rigid mounts will require a bit of foam insulation to build up the thickness.
my hed bars came with a plastic piece that slides on to the horizontal bar which looks like it would be the perfect place to mount a computer. the plastic “shim” adds thickness so that you can mount a computer without any problems. i have used vetta, cat eye and polar with this “plastic piece” and have had no problems. i’d check with hed as this piece works perfectly for me and is nice and neat. hope this helps.
Uhh. . .in a word. . .NO. . .the computer mounts centered in between the aero extensions. . .in a fairly “dirty” air place, behind my hands. The computer isn’t in the wind at all. . . Now maybe if I had bars mounted at a negative angle like Bjorn, it might be breaking wind. . .