Most of the cases, you probably just want to stick with the working formula already. These off the shelf ECU upgrades are probably your best bet than spending money on doing personalized tuning on a dyno machine.
I have done both ECU and the dyno tuning (AFC)just because the application I have setup on my car is not really that..usual. I have altered a lot of different components and parameters that makes it worthwhile to put it on the dyno machine and do an extensive dyno tuning. That and also when the car was not running at its optimal condition...needed something more to help out.
But, I would think an ECU upgrade will be your best choice for now. Also when you start to experiement and do all these trial and error tuning, you are increasing the risk of having something gone wrong on you.....
So, I say let these chip/ECU tuners make their profit and enjoy other's hard work.