I have a 2015 Four Winns powered with a 320-CE-B r.w.c. with catalitic converters. The boat has four seasons and 100 hours run in brackish water. Neutra salt was added last season. On previous boats with the 5.7 r.w.c. I always changed out the manifolds and elbows after five years. The cats were introduced in 2009 on all gas inboards. It is no surprise to me that the Volvo manifolds, elbows and cats on the 320-CE-B cost around 6K plus labor. Has anyone out there gotten to the point of replacing them, if so, are the any other alternatives, Like maby eliminating the cats, a different manufacture. I realize that there are sensors before and after the cats which all go thruogh the ecm which may complicate matters. I'm not looking for a cheap way out, just thought I would ask around for opinions before I spend the 6-9K to change them out. I'm sure I have another season on what I have. I want to have all the answers before asking the BOSS forthe checkbook. The members in this forum always come up with great ideas and opinions so I though I would again check with you on it. Again thank you in advance.