With a stock M30 in an E3 there is a few things in decending order that you can do get the ignition to work really well:
1. replace points with electronics. The regular pertronics or a lumention will do. Magnetic or optical is a matter of taste. I use the pertronics all the tame and have nothing but praise for it
2. Make sure the distributor is mechanically in tip top condition. No play in shaft, centrifugal advance and vac advance working as designed
3. Replace all ground straps on the car. Put in a few more. Put one from the cylinder head close to the distributor to chassis ground as well. Clean the grounding points on the chassis before you put the new straps on. protect with grease. Service regularly. Seriously you would not believe the difference that will make. Fm radio reception will improve greatly as well.
4. Make really sure you ignition timing is set exactly right (as per manufacturer)
5. of course make sure rotor and cap are in tip top shape
6. Make sure your coil is healty. No need to upgrade to anything, the stock type coil but in good quality (Bosch or similar) will do.
7. Make sure HT leads are tip top. Go to something better if you like (I like the magnecor leads, very good quality that will last forever)
8. Go to Iridium plugs. NGK Iridium, not platinum, not bosch, only NKG Iridium. Benefit: They don´t foul easily and will last forever. Alternatively: use regular chaep Bosch plugs but change them all the time.
That´s it. And if you can do only one thing: do #1, the points are the biggest issue with the stock system, especially now where quality points are very hard to come by)
Everything else will yield no noticeable benefit at all. High voltage coils, programmeable ignition, multi spark firing etc... that´s all very nice but you will not notice any improvements over stock+pertronics in the way the engine runs. Or rather you will if you´ve spent the money but that is psychology.
You´d be surprised at how effectively and optimally the stock ignition can ignite the charge in an M30 if only it is in perfect working order.
If you want to make sure it is: go visit DQ with his marvelous Bosch motor tester and Osziloscope.
If your engine is not stock anymore (weber sidedrafts, different compression, more cubic inches, hot cam etc.) all bets are of. Then you´ll probably need programmeable ignition and a lot of time because you´ve effectively become a motor manufacturer and have to go through the full development process for at least igniton and injection, probably thermo- and fluid dynamics as well. Can be fun but no easy task. If you care to learn about what that implies, I can recommend a few books...
To answer your question: The ignitor 3 is for the benefit of the manufcaturer, not yours. Go with the simple ignitor.
If you want to improve your emssions: do 1-8 !
and then start taking a look at your injection (the L-Jet is pretty reliable but check the cold start injector for leaking , the MAF for wear and the fuel pressure for correctness). IF that doesn´t help: your engine is worn and will need a rebuild.