If cost isn't an issue, the AEM. If it were me, Megasquirt. Some of the AEM units have had reliability issues. If you have one, you have to send the unit back to them for repair or replacement. If you build a Megasquirt and there is a hardware issue, you dig into your spare parts bin and fix it. The MS is very well supported and documented on the internet, and its cheap. I could build and throw away 10 Megasquirts for the cost of one AEM.