Not having used a piggy back tune before, I was looking forward to seeing just what this thing could do.  Let's just say I've got a smile on my face.  I had my last (well modified) car pro tuned and was very pleased with the results, so I was a bit on the skeptical side.

Stock boost for my car is around 8psi, and one of the JB4 maps (map 2) bumps it up to 12-13psi.  There's a self tuning map (map 5) which evaluates what's coming back from various sensors and makes dynamic adjustments accordingly.   On a mix of 2/3 93 octane and 1/3 E85, after some learn time & a few pulls I was seeing 17-18psi and the car has become a different animal.   It almost made me want to go 'vette hunting.