rickenbacker 4003s 4000 conversion

To the Rickenbacker experts out there: I have a 4003S (from 1995). If I wanted to convert it into a 4000 (I just LOVE the way they look and sound), what would be the best way to do it? Of course, it would still be a neck through, and that's ok. I could buy a 4000 pickguard and rewire the...