i got a stock 400ex , only things done are slip on Lexx pipe,a jetted carb, open air box cover , uni filter and ricks motorsport hot shot series cdi box/ increase spark. i was thinking about getting the Curtis Sparks advance key , but one thing i'm puzzled about, is how does it advance your timing when your just taking the old key out and replacing it with another in the same position on the crank? to me it seems as if it wont advance your timing at all. and would it be worth it with the cdi box that i have ? any info would be great thanks