...or any EMS/piggy-back CPU controller for that matter.

Once you've 'tuned' your car and are happy with the settings, are these settings reset everytime you turn the car off? That is, do you have to keep a laptop with your configuration in the car and essentially re-configure it everytime you start-up?

 

I thought it replaced your ECU entirely.

 

It does, and no it will not reset everytime you start the car. EMS is not a piggy-back, but they are calling it "Plug-n-Play" which you may be confusing with "piggyback".