I doubt you will succeed even with a bitsetting capable burner.
Use search and search for navi disc", you'll see why.
I personally also see no sense in making backup or even "backups" of such a disc.
It is for ONE car, to be used in this car, and if it gets damaged the seller of the car or the manufacturer should give you another copy, for free. That's the least I would expect from someone getting thouands of bucks for a car................
PS: There is no Dual layer dvd-rom, a DVD+R DL will always remain a DVD+R DL, same for DVD-R DL and so on.