My Red Line speakers are Type 8510 and I see (and hear) that the foam surrounds have disintegrated.  I have done the repair on Bose speakers before and I realize that these RLs are much more complex and precise.  I request advice on this refurbishment and a best U.S. source for the parts. 

Thank you!

Enter "refoam rl140" in the search box in the top R/H corner of this screen.

Thanks for that information.  I still need repair parts source information for the U.S. please.

If you must buy in the US you could try

http://www.simplyspeakers.com/index.htm

What are my best options over there? 

People seem to recommend Good Hi Fi in the Netherlands. They can be found at http://www.goodhifi.com/ or on ebay.nl as good-hifi