There's no rebuild kit to my knowledge either. I just replaced the fuel distr. on my 450Sl. I know it s not the same but they are all a complicated mess of springs and valves. I got a salvage one from Sambucci Bros. in Corona N.Y. for only $100. You might want to try them or go to car-part.com and search. If You do get a salvage one look for one that hasn't been sitting long. Mine came of a recently wrecked vehicle. You will have to have the pressures tested on it from competent shop.
Good luckhttp://www.car-part.com/ http://www.sambuccibros.com/

jmdunn