I came across your post regarding the RFX-8140. Don't know if you finally got your hands on one, but I have one that I want to sell. If you are still searching, give me a shout and I can tell you about it.
I have a fairly new 415 been stored for years. Googling info on this unit I ran across your post. I would love to use it myself if I can find wiring diagram etc...but would part with it
I have the Clarion 7770 6770 English Owners Manual and Remote Turn On Relay insert if you still need any information from it. I bought the 7770 new in 1994 but never got it installed. I want to install it now, but lack the fiber optic cable or what cd changers it will control, which is how I found your post.