I have seen the GPS modules in the past on ebay and bought one once for a guy in Scotland. It is easy tp get to, on the rear right side of the MKIV. Has a couple of cable connections IIRC. About the size of a credit card. The one I found was from a surplus parts company on the west coast. I will see if I came dig up the name. Search for it on ebay. Was not expensive. Or search for some of my OLD posts here.