I have had outstanding results with the AEM system in my car for the last two years until I started getting timing errors all of a sudden. After doing the research, a lot of people were going to the EPM system with coil on plug. I just finished getting my car running with the new setup and it runs like never before. Outstanding idle quality and throttle response with smooth crisp pulls at the track so far. The AEM system has so many options such as boost control, nitrous control, two step / multiple rev limiters , individual cylinder tuning, internal and external datalogging etc etc. So those of you who trash talk the system, you obviously were doing something wrong or had the wrong person tuning it.