body crack around door striker

This is what I use to repair the problem . There is a left and a right

http://www.dynamicrenovation.net/detail.php?ID=33

The problem is caused by worn door hinges, or not aligned . Closing the door, when the stacker does not align with the door latch , causes the door jamb metal to flex and break

my 1/4 penny input

Yep, that's the piece to use. They also have a door handle reinforcement piece for the door handles that's pretty cool.