Man +4 on Knowledge roll is not overpowered) you can easily roll 1,2,3+4. And CB is a d20 system, with standart DR of 12, even with +4, it's not going to be "too easy")
People played this class at my games, i've played it myself a few times, and it did not break the game)
By far the most powerful thing is the "Quickhacks" talent, but again, it's not Dnd, hacking is far from automatic and if are using the "standart" method, the person who plays the class, still has to roll and get that talent, they might get something else)