Where to buy Mabuchi FK-180SH-3240 Motors?

I've been looking into modding the rapid strike, and I have a friend that's modding his stryfe, so I've been trying to find some good FK-180SH-3240 motors, though can't find that exact model anywhere (Amazon, eBay, looking through a few forums). Though we have found one possible candidate, it seems to be a KS-180SH-3240 model (http://www.kysanelectronics.com/Products/Detail.php?recordID=7071) instead of the previously mentioned model.

Could someone possibly point out where I could buy some online (other than a hobby store), or if the link was the correct model? Thank you!