I'm running an Urban Offroad low-pro rack as well. The Exodus Series Platform Full. (quite a name...) It's an LR3, but I doubt there's any difference. I found it absolutely AWFUL with no wind deflector - crazy loud!
Here's a copy of a post I made on our club forum summarizing my experience with it:
I made some more improvements to the rack wind deflector.
To recap-
First I tried it with no deflector. That was 100% fail. Crazy-loud; sounded like a 747 on take-off at anything above 50 mph This led to-
ghetto-fab yellow plastic zip-tie wind deflector. Ugly, but effective. It actually worked. This led to-
Urban Off-Road 'factory' deflector. This sort of worked. It got rid of the 747 but still caused quite a bit of turbulence noise. This let to-
foam pipe insulation stuffed under UOR deflector. This worked pretty well, but looked a little cheesy and of course the foam was never a permanent solution. This led to-
Custom oversized wind deflector. I took the UOR deflector to TAP and had them make me another one only 6" longer so it would reach down close to the roof. This worked quite well up to about 40 mph, but then it starts to vibrate and touches the roof. So I ended up using some sticky-backed foam strips in strategic locations to keep it from flexing/vibrating against anything. I've now tested it to 'crossing NV on HWY 50 in the middle of the night' speeds without any real noise, so this will be staying for a while.
If I were to make another one, I'd probably make it about 1/2" shorter to keep it from touching the roof, and I'd make it out of thicker stock to help make it more ridged and keep it from flexing in the wind.
A few pics-
With the Urban wind deflector and foam pipe insulation
It's current state-