[David E. Clark]

Thanks for the reply. I used an MSD 6A on my old 1971 SAAB Sonett II (1.7L V4) and had really good results so I am a believer in MSD products. What I'm really interested in knowing is if anyone has any experience with the Jacobs or MSD or other "add on" units on an early Porsche 911. Not the replacement units, but the kind the work together with the existing CD ignition. As you can imagine, I really don't want to rip out a working stock CD unit. Do these "add on" units help or will I just be wasting my money? Both companies promise substantial improvements but I am still skeptical. What do you all think?