Ok Pipe, Jetting, Stage 3 rev limiter, stage 2 cam, maxxis holeshot tires, nerf bars, foam air filter, and an extra oil cooler mod. This is all on my 05 400 and it's pretty awesome If you do bore ht e 400 you will have heating problems to wear you dwon't even wanna put your legs next to the bike. do an extra oil cooler mod if you do bore it. Helps it run cooler and helps keep your engine alive a lot longer.