Sync3 and wireless carplay

Yes, I believe it would be safe since it would not involve the use of the reformat tool. Before you try to update it, could you please run the APIM Interrogator Utility and post the file here?

Also, in case you are not familiar with upgrading non-nav Sync units, read this tutorial. You may not have any issues at all, but if you do, at least you know what to expect and how to fix it.