Michelle is right. Deffinitly do the suspension first. Steering dampers are great but they can't help when you nail g-outs, slam into woops, or dive into corners. I race HS too, at your weight you need to get your bike ballanced out first (I'm 190lbs.), then worry about power, and finally the damper. When I bought my KDX 200, I raced the first race bone stock. I was running mid-pack but DNFed on the last lap after breaking my clutch pearch. The next race I had the fork done by Pro-action (and put on Acerbis rally guards), and finished 2nd. The fork is the biggest weakness on the stock bike, especially at your weight. Get the suspension done, then pipe and engine, and worry about the damper later. Personaly I don't use one. I've ridden with them, and they are great, but I am worried about crash dammage, and the price just seems too high. If you were racing Hare & Hound, it would be different, but for HS your money will be better spent elsewhere.
-Nick