Raymond,
I pointed Ross in the direction of
www.lambostuff.com for the jalpa airbox's and base plates. I don't think Ross is too impressed with the quality of the build though, Ross's also came with an extra pipe on the side of the air box which we weren't sure what it would be used for, it was a questionable attachment but I guess it would be functional if Ross knew where to attach it to, hopefully Ross will post a picture up so that people can give there opinions for its functionality. I haven't had much to do with sourcing Urraco parts and my quick search on lambo stuff didn't show anything.
Mike
PS: Ross, yes I am planning on starting a thread when I start the rebuild, hope I can do as good a job as you and the others have done :-)