When I'm trying to test I will use a combination of WOT logs, Torque mins and maxes, experiences between the 2 cars, etc.
For example, my car starts up in a climate controlled garage so I watched fuel trims at startup and after the initial and subsequent ACES treatment they clearly moved backwards....and after startup and when the idle drops. Scientific proof? No. Different result than I'd noticed before? definitely.
I know that KR activity on the 2013 was definitely higher on that car with E25 VS the 2015 with E20 and ACES, which at this point doesn't exist. Performance of the two cars very similar comparing ET's and trap.
I know the only thing Torrie will look at when adjusting my tune are good WOT logs. Finding a safe, low traffic stretch is super helpful. Every log I send is on the same on ramp done usually after midnight.
AJP is blessed with tuning knowledge, time, and apparently an awesome wife that supports his datalogging/tuning habit so he definitely has the upper hand over most of the rest of us. Get him some good logs though and there's no one better on this forum to help interpret the results.
I will say having an X4 and the supplied software is a much better logging tool than any of the OBD platforms that I've seen. If you were contemplating a tune in the future buying the package now would probably help you even if you held off on the actual tune itself.