It is completely normal in the entirety of the tuning world to use JB4 stacked on top of a Back end flashed ECU tune. Many are already trying this, and some new tuners are specifically designing tunes for this type combination. Then main benefit being being dynamically fine tuning boost and fueling, or integrated external safety controls for Meth or port injection systems which the factory ECU cannot provide. While an ECU tune is required to allow for increased torque demand targets, and to remove limiters to hit those targets, they are ultimately complimentary systems. If you are to pick one right now as a newbie, the JB4 is easiest to install and get a good performance bump with little tuning background. Simply plug in, set to map 2 and enjoy. As there are more tuner gettign in the game, I'd wait on moving forward with any ECU tune at this time as new players and options are eminent.