I have a Vantech aluminum ladder rack without the roller bar. It's ok and serves it purpose (hauling ladders
). Can't comment on any other brands.
Not sure which one your looking at, but the width on mine is only the distance between the roof mounting holes. I see the width on some racks extend to the outer edges of van which is probably better in your situation.
All racks create extra noise from my experience. That, and the fact that mpg go down are the reason I only mount mine when I need them. Once they are originally installed it's just a matter of 4 bolts to put on or take off.