Many years ago I engaged member Ric5 to convert a Rickenbacker 4003 to a 5 string. He did a great job on it. I never got used to the 15mm string spacing as I mostly perform with a std 4 or 18 or 19mm 5vr. So I converted it back to a 4 string. These are some of the parts he used to do it. Bridge saddle assembly, 5 string plastic nut and a tuner (looks like a copy of Gotoh compact type). If you take this conversion on, this isnt all you need. The pickups need added poles and pole position adjustment or new 5 string pickups. Free shipping in CONUS using standard USPS.