I currently own a very tired 07 wr450, and next year I am taking it to baja. To the bikes credit I have never been into the motor at all, and it still runs well, but it's just a little tired. My overall goal is to get 5 to 6 more horsepower out of the bike, and have a bike that can go 100mph, and be reliable. I'm going to be doing a new top end(OEM piston) and I am going to be putting yz cams in. I want more power from my bike, mostly to be able to run taller gearing and still have some grunt down low. High compression pistons and any mods that require race gas are out, because in baja you take whatever gas you can get. I don't think that a big bore kit is what I want either because I like the reliability of stock yamaha parts. I'm mostly curious about what people do in terms of head work and porting? I'm not looking to go to crazy, but I would bet there are 3 or 4 extra horsepower hiding in that head. I'm also curious about valves and valve jobs. Is there any power to be gained there without sacrificing reliability. I know that some people advance timing a degree or 2 as well, and I am also curious about vertex ignitions and whether there is anything to be gained there. My wr has been a great woods bike for me, but now that I have my 2 stroke I get to build more of a dedicated higher speed/ desert bike and I'm excited about it.