ok, i just talked to a guy that works with my wife, he used to be an automotive engineer and has some contacts that can weldup the new rails.
Im going to buy 3 rails from nissan, The crushed one and the 2 on either side of it.
I was picking at the rail yesterday and found it was roughly spot welded every 5 to 6 centermeters.
Ill remove the old rails, and get this guy to weld up the new ones.
Im waiting for him to get back to me.
Steve