Agreed on FMF being a good pipe thats all I run. Heres some suggestions and mods I have done to mine and 80% of my riding is woods.
MOTOR -
Pipes : Either Gnarly or Fattys(Gnarly tend to bring on the power sooner and the Fattys are more of a "all around pipe" to me). Im running the SST's and the pull hard up top and have a healthy midrange. Im soon changing over to Gnarlys. Pro Circuits are also a good pipe for the woods. Also check into US Forest Approved spark arrestors. Some riding places require them
Porting : Get a agressive trail port. I had my clinders done by HerrJugsRacing and Kevin did a fantastic job! Great power and torque.
Reeds : Boyesen and Vforce make great products. Few extra HP and better throttle responce
Performance head : Milling the stock head can make good cheap horse power. Or if you got some extra cash go with a name brand head, CoolHead, NossMachine, FAST. Im sure im forgetting some
Clutch : Barnett Dirt Digger with BelRay gear saver
Air Flow : K&N filter with Outerwares
COOLING SYSTEM -
Pro Design : Billet Impellar and EZ Drain cover.
Coolant : Engine Ice. Awesome liquid
Radiator : Aluminum oversized radiator will keep it nice and cool due to the lack of air flow in a woods. I have this on mine and what a difference it made!
CHASSIS -
Tires : ITP Holeshot Gncc or Holeshot HD tires work great. Havent heard much about the Quadcross XC tires. Maxis rzr tires are good too. Cant think of the exact name but the Bill Balance ones are what im talking anout
Rims : Douglas rims with beadlock or ITP beadlock rims
Axel : RPM, Durablue, Gforce. Anything stronger then stock. Possibly wider stance, but also want it narrow for tight fit between trees and such
A-Arms/Swingarm : Way too many to list. "Gullwing style" a-arms alow for long travel shocks. If you get a different swingarm do it right and get the round style carrier for easy chain adjustment. Possibly the worst thing about a Banshee right there Lol.
Shocks : Elka, Works, Ohlins, Racetech, Fox, iShock. So on and so forth. This will help out tremendously with hadneling and fatiuge. Even used YFZ450 front shocks and a Raptor 660 rear are a great improvement over the stock Banshee setup.
Steering Stabilizer : Im not real fimilair with the well known brands but Im interested in the Streamline one. Again this will be a big help.
Footpegs : YFZ450 pegs work great
Brakes : Snag a used set of calipers from a YFZ450 or go with EBC setup.
Dont mean to post alot of blah blah blah stuff but I tried to think of everything I could from my setup and my future build plans. Hope it helps!!