I actually did a swap from symphony I to RNS-D to RNS-E for my B5 S4. The process is pretty simply. All you have to do is make sure the plug-n-play adapter you get is correct. TeddyB can make a custom harness for you if you're afraid to mod the adapter yourself. Steve Z1 is the guy that I got my unit from and his RNS-E package is ready to go. I did not have to mod anything. In additional to the package, you might want to pick up the cangate from bjarne to correct the clock problem on our B5 and C5. It worked wonder. Hope that helped.