Is this SCT a hand held device. And does it keep the tunes loaded on it(how many tunes can it hold?) so if need be I can up load the factory tune?
Yes handheld unit and yes it keeps your stock tune. When you plug the unit in it will ask you what tune you wish to upload low/mid/high they tell you to start with the low and work your way up (depending on which octane of gas is available in your area).
I went from low to high and skipped the mid but i have 94 octane fuel in my area and the car ran just perfect. I have never plugged it back in since, but i'm sure if i did one of the options would be uploading the stock tune. Like I said with the tune the car will run better all around, (throttle response, fans come on sooner, etc) I did notice that the car "pops" more a decel after doing the SCT tune.