In large bowl mix Oreos, flour, and sugar together. Drizzle with margarine and mix until all ingredients are coated. Press dough into 9-inch pie pan with fingers and chill in fridge for approx 1 hour to firm.
In microwave safe bowl, place caramels and 4 tablespoons milk in microwave for approx 1 minute or until caramels are halfway melted. Remove bowl and stir until mixture becomes smooth (place in microwave again if caramels aren't melted enough).
With a mixer or in a blender, blend on high the cream cheese and condensed milk (you may want to break up the cream cheese and add it to the condensed milk). Once blended add eggs one at a time. When all ingredients are mixed let the mixture beat for about 1 minute.
Coat pie crust with caramel sauce until all edges and bottom are coated--put in fridge for 10 minutes.
Remove pie crust from fridge and pour cream cheese mixture into pie crust. Place in oven for 1 hour to 1 hour 15 minutes at 300°F Remove when edge is slightly golden or when toothpick can be removed cleanly.
Let cheesecake cool for approx 30 minutes.
In double boiler, mix 1/4 cup milk and chocolate on low heat; stir frequently. Drizzle chocolate over cheesecake.
Place in fridge. Take out when ready to serve (if you want to serve right away, place it in the fridge for 15 minutes).