Man, I feel for ya. I quit smoking nearly 2 months ago. Cold turkey. That first week to 10 days is the worst let me tell ya (as if you haven't already figured that out). When I was younger people used to tell me about sinking money into a worthless old ford. But when I spanked that ass on the road, they'd shut the ---- up. I still get mad and have my fits just like you did with the heads. But it will get better, trust me. Just tell them people to back OFF. Well, it worked for me anyway. Keep your chin up.
On a side note, it probably was the ignition module. And there is one on your car. Should be on the fender. I hate to hear of anyone giving up on a mustang, especially the way you have. I just hope I don't hear you are on the road in some riced out fwd car or a camaro.