About mid 90s I caught what was probably the beginning of a movie that had a dude and a hot chick in a Porsche that managed to piss off a biker gang going down the road.   The dude wrecked the car and was killed, but the gang caught the girl and stripped her while she was standing up and sliced her with a knife diagonally
across the chest while she was screaming "Mama, Mama!" before doing whatever else.   That is about all I remember, but hopefully someone out there knows it?

It's usually on the front of the DVD case.