I didn't think anyone has solved the hiss problem with the land cruiser. I think you need to replace the amp. I have an LX so didn't have the hiss problem, but replaced the amp anyway so I know that worksI have a 2004 Land Cruiser with the JBL speakers. I have upgraded the speakers to new JBL Clubs, with factory sub. But haven't touched the amp. This a project car with my kids so we are trying to keep within budget