I'm using a Mod Quad filter system (K&N style filter) available from Rocky Mountain and PRM skid plates. The skids are holding up fine. Their nerfs have a lot of vibration because they mount to the front engine mount but they make good quality products. I believe Pro Armor has skids too.
08 700xx Barker's exhaust, Mod Quad intake, 13t, PCIII with Bo White map, Precision Steering Stabilizer, L8TON Sway bar, PRM side bars, PRM full skids, Pro Armor Dominator front bumper, RAZR2 on front, RAZR on rear
12 RZR XP900