'94 9000 CSE question

I'm replacing the head gasket in this car, and the mechanic, although a
true gearhead with a great reputation, is not familiar with Saabs. So
far, he has also suggested replacing the following while he has the
head off:

- thermostat & gasket
- valve stem seals
- head bolts

I have the following questions:

- Is there anything else that should be checked/replaced?
- How many valve stem seals do I need to order? Intake & exhaust?
- Is there anything he needs to know particular to this engine that
isn't in the book?
- Which is better quality: Elwis or Elring gaskets?

Thank you.

Shrdlu