The physical arrangements are very different. My point is that you need to decide how you want to use your lights, and whether you can get double-duty out of the fog section.
In my situation, the fog section is used continuously as a daytime driving light, and maybe once a year as a fog light. In any event, it does both jobs very well.
If you install the 500E components you'll need to do your homework on the physical fit and electrical conversion.
Let me know what you decide.