You can use the cruise control button OR competitive mode to activate/deactivate the tune. Or it can just be on all the time. Up to you!

It's $465 total for the premium tune with a cable.

 

I've never had a single customer blow an engine to date and we've worked with Trifecta on over 1000 cars.

 

I have trifecta activate on the comp button

Also went through BNR, and they have been an awesome company to deal with!

 

I debated which button to put it on. When The cruise on is tune off. Advantage is you can activate with the left thumb at any time, even while accelerating. When the boost hits you do need both hands on the wheel. I, so in my case my wife does not use cruise control and if she pressed down too hard she would s**t and lose control.
On the T/C button you have to let go of the wheel, press it twice or hold it down for ESC off. If you have your hand off the wheel to press it and are foot in it Hang On! it will pull on you , be prepared!
Over all either is good, it depends on your needs.