Yes, you can add two Era 300s as surrounds.

As above both will work as surrounds but when in that mode the Auto Trueplay, voice control and Line inputs will not function.

The Bluetooth functionality of the Era’s also likely to be disabled when used as surrounds.

Agree just turns them into dumb slaves to the Home Theatre unit.

Thanks everyone. I knew they would work as surrounds. However, I was more wondering if I will still be able to run the two subwoofers once the 300's are added as surrounds. I know it's a dumb question, but I haven't heard anything specifically about two subs with the 300's. I can't think of any reason why it wouldn't work but It would be just my luck that I would buy them and find out you can only use one sub! Lol!

There is no relationship between surrounds and subs.

You can add 2 surround speakers and 2 Subs (with at least one Sub being a Gen3) with the Arc.

All I needed to hear! Thank you! I said it was a dumb question! Lol