I am using the MK20DX256VMC10. The closest BSP seems to be twrk20d72, but upon closer inspection the memory model file is MK20D7.h and it doesn't support MK20DX256VMC10. The MK20D10.h does support this part. So, I made the modifications, and I still run into problems.
Also when I combined Processor Expert generated files (IAR: Project Connection), I discovered lots of complier issues. ...I believe Processor Expert uses GNU compiler, while IAR uses there own.
I have sense back out the processor expert generated files.