You really don't need the extra memory card. You are talking about Nav V, right? Connect it to your computer, and assuming that you use Windows, access the GPS with File Explorer. First thing that you want to de is copy everything you see, down to all the sub-directories, to your computer hard-drive. This is your backup. Now access the files on the GPS and delete everything that you know for sure that you don;t need. Files such as the manuals, especially all the ones in other languages. By the time that you are done, you will have more than enough room for the updates. I have had mine for several years now, and had gone through every single updates (maps and software), and still have plenty of room left.