Plugin feature for C# WPF application.

Question

We'd like to know what kind of architecture to add plugin function into our C# WPF application.

Plugin requirements

• each plugin can be loaded dynamically ( can stop dynamically. )
• each plugin has common I/F with main application.
• avoid app crash from each plugin (So we think each plugin must run as process.)

Currently, we have two ideas.
a) pipe ( each plugin is pipe server )
b) COM automation server ( each plugin is COM out of process server ) : this advantage is event I/F.

Question

1. Another ideas.
2. merits and demerits for each architecture.
3. What is recommended?

Any ideas and suggestion are welcome.