I'm amazed how many people still consider speedbox for a gen4... if you dont mind a timer every time you stop, and bricking your motor if you disregard the timer, only be able to set the speed in 5km/h increments, and no security code to activate, the speedbox chip is your way to go :P
500km with volspeed v3 on a gen4, no issues, super nice chip that allows you to secure it with a code, set your speed per 1km/h, and even have a dynamic mode, and no countdown timer.
all in all, the volspeed is the better (and cheaper) chip than speedbox.