Look at the main site....
http://www.gasgasrider.org/html/parts_crossover.html
This isn't completely up to date and frankly when I get an e-mail from a member that something fits - I am not sure unless I see it myself as "beauty is in the eye of the beholder".
One person's "fits like a glove" is another person's "wow,
I had to use a small sledge hammer to get that square peg to fit into that round hole..." 
Jeff