Yes, a DiabloSport tuner can do all the things mentioned above, but increasing HP/TQ and reading/clearing DTCs is only half the story...the exciting half I will admit, but still only half.
For me, the much more useful aspect to the tuner is its ability to tell me what's going on inside my engine via the datalogging capabilities.
By using the tuner to record datalogs while driving and then studying those datlogs (with DiabloSport's DataViewer software), I have learned more about my car and how it reacts to various changes in the operating environment than I ever could just reading articles and manuals. This particular aspect of the tuner is invaluable IMHO.
That doesn't make for a sexy bullet point in the 'Pro' column of a "Pros vs Cons" list of tuner ownership, but that's fine. It's a definite plus to having the device.
After all, the tuner is described as a power-adder, and as we all know, knowledge is power, so in that respect, the tuner lives up to its billing for sure.
Nuke