I was in a car where 43 bags of heroin were thrown on the seet.

The police and prosecutor will normally charge both occupants with possession. The drugs were in the vehicle and there were two people in the vehicle. If one person will not raise their hand and accept responsibility, then the police charge both occupants.  I am assuming that the other occupant will not except responsibility for the heroin. Your problem is that the police may want the other occupant very badly. As such, they will threaten to punish you severely unless you cooperate against the other occupant in the car. You have the choice of testifying against the codefendant. Please call to discuss.