I agree. Tomorrow I have to take my other car in for a new airbag. My fourth trip to the dealer about airbags. If they get it done in a timely manner I'll try to get it loose. If I break things I can always drill out the screws and use self tapping screws to put the rebuilt module back on. If that doesn't work I'll just replace the whole shebang.
Good luck with the old Datsun Z car.

 

x2 on drill the heads off. the computer will slide off, revealing the solenoid shafts. Then you can try to twist the bolts out.

 

So today I will see what five days of soaking the screws with PB Blaster has accomplished. I hope at least one more doesn't break.