No difference in the radio. Even the CVO software will run on a non CVO. Just has a little more programing for other tools the CVO has.
Once installed you can flash update the radio to non CVO software if you want. Of leave it using CVO software.
You will not get the warning if it is not there. And on the CVO radio you can just install the non CVO software just as you can install the CVO software on a non CVO bike.
Picked up the 6.5 radio on Sunday. Took about an hour and a half to remove the 4.3 and install the 6.5. Powered up the unit and it works perfect. Can't use the radio until I get a flash at the dealer Thursday morning for the boom II amp and speaker I have. Everything else look pretty awesome. I got a great price also