Xcal 2 or predator tune on tuned car

[r6bullet]

Ok, the title may be a bit confusing but this what I am wanting to know. I may be purchasing an 04 cobra that is at a dealership. It has an upper pulley and catback exhaust. The vehicle appears to have some items returned to stock, I am not sure if the vehicle is still tuned. My bet is that this vehicle was reflashed to stock so the tuner was unlocked an he could sell it. Lets say that the vehicle still has a custom tune on it, do you have to start with a stock tune when using the Xcal 2 or predator? What would happen if I tried to tune a car with an Xcal that already has lets say a predator tune on it?

I am just not sure how the tuner works, does it take the stock tune and add to it or does it just save it and load a completly differant tune? The car is located a couple of hours away so I was thinking about just bringing a tuner with me before the drive back.

Sorry for the long post, I hope that makes some sense.:??:
Thanks

 

[Blown04GT]

I am pretty sure the xcal will pull the tune that is in the car and keep it as the "stock tune" and then you can put the xcal tune in the car. Make sense?

 

[r6bullet]

I am pretty sure the xcal will pull the tune that is in the car and keep it as the "stock tune" and then you can put the xcal tune in the car. Make sense?

Yes that makes sense, I just didn't know if the new tune was based off the stock one. If I decide to buy the car I should be ok with just installing the pulley tune on the predator/xcal (not sure which one I want yet). Hopefully that will work, I even thought about having them reflash it to stock for me that way I know what I am saving as the "stock tune".

 

[Blown04GT]

If you do get the car, take it to a dyno to get it tuned with whatever handheld you decide to go with. It will be worth the money.