318 MAX fuel economy builds?

I will agree with keeping the lean burn and electronically controlled 2 barrel- that's what they were designed for.

...and it's $0 if they are working.
The Leanburn was a recall! It tends to suddenly stop working when it gets hot. This will happen when you’re driving. The Leanburn should be replaced with an earlier style ignition at the minimum. AKA - orange box though I like the chrome box better. IMO, go see Don @ 4secondflat.com for an ignition system.