Quick Handheld tuner question

I will preface my comment with a big I THINK:
I think that as long as the original owner reflashes his car with his original tune, you should be able to get the SCT to accept your car's original tune then apply the custom tune. You may want to check on one other thing: when I ordered my SCT from Brenspeed, they asked me for the number from the tag on the computer under the hood of the car. I don't know how much of an issue it might cause if the two computers are different. Just something else to run to ground before you part with your $$

the reason they asked you for that code was they sent you the scanner with a tune on it for engines with that particular code. If you take yuor car to the dyno shop and get it programmed there, then that doesnt matter (or program it yourself). and that is correct when you put the tune in your car it leaves the tuner and is replaced with the stock tune your car had. when you put the stock one back then you can use the scanner on another vehicle.