There are many having ignition issues with the digital ignition boxes and from what I'm hearing they are caused from bad ground and the solution is pretty simple run a wire from the back of one head to the other and them to the negative side of the coil. This grounds the ignition system and Is fixing most of the issues people are having with the digital boxes.

Another thing I'm hearing is that you shouldn't ground anything to the roll cage, I know that doesn't make sense but it goes not ground properly especially in non-chassis cars. Run a ground wire from the battery and don't rely on the cage.