I would agree if SV were talking about different brands of subs. They were not. Their suggestion was not to use an SV 16-46 PC+, (a more expensive model) with an SV 16-46 PCi (the sub I currently have). In other words, buy another SV 16-46 PCi rather than buy the more expensive sub, (an SV 16-46 PC+) which might cause you problems. A company who was just out to make a sale might just try to sell you their more expensive model than give you proper advice. Go figure.