steve,
I'll try to avoid the last time we went around on this issue.
You're right, there is no clear winner in this debate. I've tried the following combinations:
1) Pertronix I1 with stock coil
2) Pertronix I1 with Flame thrower Coil
3) P I1 with flame thrower coil and MSD Digital 6+
4) Duraspark 2 with flamethrower coil and MSD Digital 6+ with 8mm wires
What do I recommend?
what ever fits your budget. I found no real difference in performance between #3 and #4.
Why did I end up with #4? I wanted to be able to us stock over the counter available parts if I ever get stuck somewheres. I was tired of carrying point around in my trunk just in case (never needed them though). Also, someone gave me a DS2 dizzy for free. ALso, since I intend to go EFI eventually with the Holley system, a larger cap and rotor will allow me to make use of timing controls the ECU has without worrying about rotor phasing.
Dwell control? Don't need it for DS2. Already compensated for. You don't have to worry about the gap on points or the gap between the pertronix and sensor under the cap. It is solid state on the DS2.
control spark duration? does I2 do that? I'm not sure, it didn't seem to though.
Dial in retard from the cockpit? MSD makes that system.
What is the advantage of the MSD? Multiple sparks, more energy per spark. I get about 2MPG more on the highway (yes, I tracked my mileage before and after, I write my mileage down every time I fill up on gas). Is that a big deal? Up do you. it's about a 10% improvement for me, so that's about $3 a week it saves me, so it saves me about $100 a year (I don't drive the mustang december to march). I drive about 10k miles a year on my 65. I also have a much smooth idle. On the model I got (a little more expensive) I got dial in rev limiters (2) and 2 voltage activated timing retards (for like NOS or whatever). With the MSD (on both DS2 and Pertronix) I was able to open the plug gap for more power and mileage. with pertronix and flamethrower, I opened the gap to .042. Now I'm running .055 gap with no problems.
The real point here is this. upgrading to electronic ignition is a good idea. The systems are comparable. If you want a cheaper system, then go Pertronix witha flame thrower coil. You'll notice an immediate difference.
If you are just looking for a good, cheap upgrade, go with #2. You'll be very happy with it. If you decide you want MSD at a later date, you can add it on. It isn't necessary to run the pertronix unit. It's also not needed for the DS2 set up actually.
Slade