the profec b's are fine. they do have the function GAIN or fuzzy logic or whatever trust call it which is supposed to reduce lag. basically it holds the wastegate shut until the desired boost pressure is reached rather than 'bleeding' off the air. it depends from turbo to turbo how much an EBC reduces lag, but dont expect miracles
the biggest advantage is now youve got an electronically controlled solenoid which you can adjust from inside the cabin depending on driving conditions or how hard you want to drive. so you dont have to hammer the car all the time. this is the biggest advantage i found from the 'upgrade'.