My 2008 RRS has some buttons stuck and the cd eject button has come out (like this when I bought it). My question is its the basic system with single cd player and I want to replace it with a 6 cd unit so would this be a straight swap or do I have to replace like for like. My current one has CD560 printed on the front. Looked on fleabay and FB but can't find the same unit but plenty of others with different numbers on them. It's also got the sat nav screen if that makes a difference.