I called ECU Doctors this morning..
They said there could be a communication issue between the DME and M531. Wiring is not suspect as the car operates with no faults.
Dealer is going to remove the DME, M531 and I'll send 3 keys to ECU Doctors. They said there are two options..
1) Fix the problem with intermodule communication or buy a rebuilt unit
2) They have a workaround for the immobilizer.. essentially to disable it so any fitting key will work. See
Immobilizer Removal for Porsche Boxster ECU DME 0261204605, 0 261 204 605 - Specialized ECU Repair
They said if I send the DME, M531, and keys, that they will make it work. Estimated price is $675-850. Turnaround time is 3-7 days. I spoke to a local independent Porsche mechanic and he said that he uses ECU Doctors for all his DME work.
-B55er