No adaptor needed for any K or R bike (at least back to the 1150).
If you are going to do your own service and maintenance, then just bite the bullet and spend the cost of the first service on a GS911. I have the Bluetooth enthusiast version, but if I were buying now I would buy the latest WiFi version.
Whatever you do, do not buy a cheap Chinese copy, they really do not do the business!
Go to Hexcode.co.za for the home site!
Google will find you the cheapest deals, as always!