When I bought my C1 it was missing it's airbox and had been setup for pods (larger jets, 4-1 header), bike had sat for a long time and had 2 ratty pods on the carbs. Upon hearing all the negative things said about pods, I wanted to go back to the stock airbox, but in my case it turned out to be less expensive and less hassle to just buy a new set of pods than buying an airbox, boots, hoses, and jets, so I bought a set of Unifilters for about $65 and a crankcase vent filter for $3.50, and I do not regret that decision. I had taken the carbs apart and cleaned them so I had to re-adjust the airscrews, which was not a big deal, took a couple days to get them dialed in. Never had to adjust jet needle height or re-jet as they had already been dialed in by the PO. Never had any problems with wind gusts, and I'm 6' tall and have driven the bike through some 30-35 MPH gusts. Throttle response is awesome, definitely screams on the top end. Never ridden the bike in the rain (and don't intend to if I can help it), so I can't say how the rain would affect it.
Edit: Checked the receipt on my Unifilters and they cost $75 after tax, not $65.