I currently have a 2005 trx400ex. It has kn filter and full fmf exhaust. What other mods are good to get, money isnt relly an issue. give prices too, and how much more power/speed.

 

you can drop in a cam. It's pretty easy to do. I mild cam would be about 125-150.
If you want an aggressive cam then itll be about 350-400. But with the aggressive cam you will need aftermarket valves. Valve spring and rocker arms. Go to sparksracing.com to look at them.