I've felt your pain. I'm 200 lbs+ and the first good set of railroad tracks I hit with my stock B6 suspension got me good! The forks spike your shoulders and the shock spikes your back, ouch!! At your weight the only thing you can do is what blackbandit outlined. Go with 15wt oil. Its an easy mod and shouldn't set you back more than $150 (springs, B12 shock on ebay, and some fork oil). You'll be amazed at the difference.