And then there is G12+ and G12++ also. In my owners manual it says use G13 coolant, if absolute necessary I can use G12++.
I'd guess its down to additives and corrosion protection.
Here is a...
If the previous mapper locked the file you most probably be able to read the file off the ecu. But you can always write a new file to it replacing the old one, if not the previous mapper has done something really stupid.
How do you know the previous file is the stock file? If the car puts out...
I've got 322 hp with 728 Nm of torque from my CDUC. I'm happy with this tune and had the TCU tuned at the same occasion. Almost a year with it tuned and 131k km on the ODO there has been no problems. No hardware mods done to the car.