I know of no settings that can be "adjusted" via OBD-II, except maybe adjusting vehicle speed for different tire sizes.
Professionally, nothing beats the SnapOn tools. Their are several models and I can not tell you the differences. BIG $,$$$ with all the options ! You can save money by buying used, but you will likely have to update the software.
I have been researching this topic on and off for the past couple of years and have come to the conclusion that the best "bang for the buck" is the Actron CP9680. Actron is owned by Bosch. The vast majority of the EU powertrain controls are designed/manufactured Bosch, so I consider that a big plus. This model also covers ABS and SRS on most vehicles. It also does real time data and record /playback.
The biggest negative is, even though the software can be updated, it has not and only officially covers vehicles through 2013MY.