I have used the JB4 piggyback on a variety of my cars.. as well as friends cars and I do like them for what they do. Keeping factory failsafes, steering wheel controled interfaces, and not flashing the DME/ECU I do like. I have to admit, however, that I haven't been in an MHD flashed car to compare back to back.
Either way, it is not unlocked, so ECU flashing isn't available.
I'm hoping for a little bit smoother of a ride, as well as a little added HP. So far I have not experienced the hesitation issues, although I haven't purposely tried to reproduce it. I also did not shut off my pedal tuner yet to see if it helps. Still sending logs back and forth to Terry. The car boosts high and kicks in the failsafe a lot. I also don't have the time nor straight-aways to keep on editing and driving around
