WC is already replaced by the WCS :-).... But basically the change is shims under the sleeve, WC has no shims, WCS has a 0.1mm shim... Gives you a little more high end RPM, with a little sacrifice on the low end torque....

Are you sure that wcs has 0.1mm under and not 0.3mm?

As far as I remember all mine had 0.1mm, but I can double check later with those WCS we have on stock.... Will revert :-)