Actually, there are a few good aftermarket fuel injection systems for the do-it-yourselfer. The good ones allow you to match the fuel delivery to the engine based on exhaust oxygen content, barometric pressure, air flow, vacuum, engine temperature, exhaust temperature, and ambient air temperature.
You can map fuel to air ratios based on all the above parameters. The only thing the aftermarket ones do not do is dynamic adjustments based on the octane and ethanol content of the fuel.
It is not a cheap solution, but it works really well, once you get it all dialed in.