I run the AEV Snorkel and Pre-Filter on my JKUR and as others have said it is for dust control. Running trails in the Arizona desert is dusty business. I am typically the lead vehicle for the group I run with or I am solo and while I am not plowing through someone else's dust cloud, if the wind is trailing or swirling, I'm quite often in my own dust plume. The Pre-Filter does wonders at preserving the filter in my air box.
The OP asked about wind noise and I have to report that the snorkel itself does not make any noticeable wind noise, what I do notice is a whistling where the air vortexes through the underside of the Pre-Filter in one particular spot. A small piece of tape placed strategically on the grill under the Pre-Filter remedied this.