Well first of all, I wouldn't say the xtra-10 is higher performance skid. They were designed for two different purposes and do a good job in their respective areas. Problem was that Polaris couldn't get the best qualities of both skids into one system which is way they developed the edge skid which everyone says is a much better all around system then either the 10 or 12.
The xtra-10 is a rising rate two-way coupled suspension while the xtra-12 is a falling rate two-way coupled suspension.
But rather then get into a bunch of techmo-muble-jumble there is a excellant article on suspesions here:
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