My trial set up is about perfect, in my opinion here is what you should do, for performance: a set of pro circuit pipes, a cool head with 20 or 21cc domes, advance your timing +4, get pods (if there will be lots of water crossing just remove your airbox lid and get a better filter). For reliability: a high flow water impeller, 28mm carbs, (i wouldnt go much bigger for riding trails) stock gearing, maby +1 or -1 tooth in the rear, a good chain, i reccomend D.I.D X-ring gold chain, reverse your rear wheels, get front wheel spacers for cheap to help handleing, a better set of lights will help u out if you do alot of night riding, i also think the tire makes the bike, so i run holeshot xcts i have a 22 on the rear (nice lift for rocky trails) a temp guage will help you out on long summer rides, for rider comfort: a anti vibration steering stem (lonestar), some nice fat bars(renthal), maby nerfs? But generally just think: quick, with good traction, and power for any hill.... thats what you should keep in mind when building a trail shee. Hope that helps.