The credits and device are associated with your account, not your computer. I've used several different laptops to tune the same cars. Just make sure you keep your stock reads in a safe spot. MPVI2 does require an internet connection though from what I can tell. I'm not sure what it is doing. I've had to tune my cars at the race track in the middle of nowhere before but I had SCT or MPVI1 which neither required an internet connection. Wouldn't be hard to do a wifi hotspot on a phone though.