You're looking for information on Need for Speed: Payback, specifically a save game with all cars unlocked at 100% completion. Here's what I can gather:
“The House isn’t real,” Tyler said. “But this save file is. Every car is yours now, little brother.” nfs payback 100 save game all cars
From a legal standpoint, modifying a save file does not violate DMCA in most regions, but it . EA can ban your account from online services if detected. Ethically, it’s a single-player game — many argue that after finishing the story, using a 100% save to free-roam with all cars is harmless. However, using it to gain an unfair edge in multiplayer (if possible) is widely frowned upon. You're looking for information on Need for Speed: