I find the Megasquirt 1 V2.2 board to be the most bang-for-your-buck standalone EMS available on the market today. I picked up my MS1 kit unassembled for only $120, which is cheaper than most interceptor units, AFPRs, etc setups you can buy. Coupled with the Megasquirt N Spark Extra firmware, the MS1 has everything I need at a great price, plus it's an excellent tool for learning engine management and control systems. Using the MSnSE firmware to control ignition will require some modifications to the assembly, so I will cover these first.