I do agree it is a lot more difficult without the right tools. A dyno and a wide band (with EGT compensation) are tools that should, nay must, be used when tuning an engine to it's limit.
Another thing that makes it all very interesting is the different ways that
ECU's are tuned, i.e.
MAF, MAP (speed density), Volumetric Efficiency, you need to have an understanding of how each is different before you can begin.
Too much timing will kill an engine before bad AFR's, and timing equals power, rather than leaner AFR's, which have very little effect.