I've been a car hobbyist for years, installing and modifying my own fuel injected turbocharger system and such. One of my friends in the hobby who has done interesting things with engines and so on, got involved with Mega-Squirt years ago when it first was created. Basically it's a universal simple fuel injection system that can be managed and reprogrammed. I think it is a closed-loop system, reading a Oxygen sensor, a manifold pressure sensor, and calibrating fuel delivery. New versions can also intercept ignition signalling from the flywheel sensor and adjust timing. Not sure if there is a knock detector function or not. Now, this is mostly a car-hobbyist system, but it does seem to enjoy a good reputation. Every car I've had in recent years is fuel injected with zero issues. I'm just throwing this out here to see if fuel injection as a way to move past carb issues, get more precise fueling and better performance is happening on KR's. Personally, I'm looking (hoping) to build a near-original KR1, and keep it as simple as possible (other than a possible retractable tri-gear, in-flight adjustable prop, belted redrive, and turbocharger system, and full autopilot, LOL). Anyway, here is the megasquirt info: http://www.msextra.com/
-Chris