... But dynos are not the real life...
There are many dynamometer types around. Hub dynos, rather than roller dynos, provide the benefit of direct coupling of wheels. No slip can occur with hub dynos so they allow for repeatable conditions. Heck engine dynos as used by manufacturers are in temperature controlled rooms.
Problem is, dynos can never be better than the operator. At the lower end of the market, the fact that many chase kw’s also puts pressure on them to fudge the numbers a little. Like all tools, a dyno can never be better than the tuner.
Roads are less repeatable but are just another tool that a tuner can use. Just like a dyno, a road can never be better than the tuner.
...I failed badly trying to leave a Stinger behind...
With the stinger, being turbo charged, I’d assume there is lots a good tuner could do in software alone, much more than could be accomplished in a naturally aspirated engine (with only a tune). Obviously, fuel quality would be much more important, post tune, if one also wants longevity