Shimmed stock needles, stock jets, Interstate springs, K&N Filter, no pre filter, Cherrybomb glass-packs in truck stacks. I tried two Dyna Ignitions, both at setting 7, both brought instant gratification and a smile (when they worked)
First one was sent back and they replaced it free of charge. Second one developed the same problems quickly and worked intermittently on not too hot days. The second unit was sent back for a full refund.
Now I run the same setup with a 6 degree TW and have had it in for maybe 6 years trouble free. Runs like a raped ape with no flat spots.
I had VERY BAD mid range flat spot, that's why I started playing with it.
I have friend who has been running his dyna for about 80k now and trouble free.

Me not so lucky. I get the same bang for the buck for a fraction of the cost.