x3. It's not a cheap alternative and regardless of what system or who you buy it from, you will need some sort of support. Be sure that the system you choose comes with the support that you are comfortable with. If you are reasonably knowledgeable and willing to read and learn, the Megasquirt is a compartively economical setup while some of the other systems are more "plug and play" you will still want some decent support. I went with the FAST XFI setup becasue of the support and the flexibility of the system. Here's a shot of the install. Has been running on the test stand but not quite ready for the road yet. We've done the cold start and idle tuning but still much more to go.