1. My personal tip/trick for all the Bing carb issues that show up in every airhead forum is Mikuni. Instant throttle response, set-em-and-forget-em reliability and at least a small boost in gas mileage. Rocky Point Cycle has them. Pricey, but absolute reliability.
2. As to the K&N issue, I bought one 9 years ago, I follow the cleaning/oiling procedure, I got no complaints.
3. Batteries? I got one of those Omega(?) batteries on ebay($50?) about 6 years ago, never had to charge it, it gets washed off twice a year whether it needs it or not.
TIP TO NEW GUYS: Use GL-4 rated synthetic gear oil in your tranny. The transmission is the weakest point in these otherwise bulletproof motorcycles. Personally, I use Royal Purple 75w140 MaxGear.
Ride Long, Ride Safe