I have a very early 1963 230sl vacuume advance, installation of the 123ignition was very easy and straight forward. All fuel probs have been taken care of. I had the wrong distr. (vacuume retard) installed by PO. After all the incredible knowlege and info on this web site, I realized with the new dist. ATDC it was horribly retarded (not PC) as I advance the dist more and more, the engine came to life. I finally got within the limits of the guage and hold down screw and dwell to 38, I have fell in love with my car all over again. It runs incredibly well. I was racing around the neighborhood at 1100pm last night, I ended up the the advance curve set at 8. I am waiting for an email from manufactuer for a tuning recomendation.