I had my distributor (1966 230SL) rebuilt, then installed Pertronix myself (Pertronix 1864LA), and I'm perfectly happy with it. Easy and works perfectly. I even faked the wiring to the ballast resistor (making it nonfunctional but present for "looks"). The rebuild, without the Pertronix, was by Glenn Ring (a site on the internet). It was reasonable but I don't remember how much, and it came back beautiful.
Tom Kizer