I purchased my Carbon 7s last year. John provides a 30 day trial with right to return if dissatisfied He knew I was busy moving into a new home told me that I need not be worried about the 30 days. I got back to him after a few days and responded to him that he need not worry about a return.
Regarding the subwoofer discussion, the Carbon 7s are not in need of a sub as the LRS+ are in a small room. There is far more information below 50Hz with them.