by radsdau » Tue Oct 25, 2011 6:22 pm
Correct. Save a copy of your current/original ROM before you do anything else. If it all goes pear-shaped, you can just put it back to how it is now.
And make a backup. These ROMs have security codes specific to your car, so if you lose it, you'll be stuck with a car that doesn't work.
Start tuning from a copy of your ROM.