We are just starting a new project and are using JBoss Developer Studio / JBoss EAP. This ships with Seam 1.2 / JBoss 4.2 and i supported by Red Hat. We are using jBPM as well.
I am wondering if I should update to Seam 2.0, and if so should I just replace the Seam folder in the JBoss-eap directory.
Technically, JBoss doesn't support Seam 2. So it depends if you are after support or not. If not, go for it.