I have an aftermarket lid-less box with a K&N and an outerwears. Similar to removing the lid and having the pro design. The only issue I have is with water. If you are riding anywhere remotely wet, get the lid. Most of you fellas are lucky enough to ride the dunes. If that is what you are doing, don't bother with the lid.
Have a nice day.

 

I've ridden in alot of water with no airbox, K&N with outerwears and my boots have always been dry as a bone, I've even stopped, pulled the air filter off right after going through water and still, boots dry. Just don't submerge the filter, that'll probably get ya some water where you don't want it.

 

im leanin a lot toward the pro design setup...

 

Well keep leaning because I have had both and was a little dissapointed with the powerlid. The powerlid is fairly pricey and I don't know if I am alone here but I could not get the outerwear to stick to the lid and I tried quite a few different glues. The pro design flows more air. I have not had any problems with water but I have found water in the bottom of my air box. I usually don't hit the puddles to hard though I don't like getting wet!!!

 

When I was running my airbox without a lid, I also had alittle water in the bottom of the airbox but nothing was sucked up in the filter, those outerwears really do their job.