From what I can find, it isn't the end of the world if your car is backfiring. This is more because it means something else is wrong with your vehicle than the actual backfire causing issues. Some people want their vehicles to "backfire"; however, this is more of an "afterfire," meaning that leftover exhaust is caught on fire after it has left the engine. This is generally what you see in those modified cars, where it is obviously on purpose.