Never used their distributor but many of their kits. I and II.
The next I buy will be the III. Now this is just my experience but have run the I in two different cars on the track and both took 6 grand shifts no problem. With the II you by-pass the ballast but must upgrade the coil to a 0.6 ohm.The III works with a .032 ohm coil.
I didn't change the coil on the first II and the car ran like crap. The old saying "when all else fails read the directions" did apply that time. I too carried a spair but in 10+years none have failed. So I guess the quality of their distributor should be as high.