How do I upgrade from ES2 to ES4?

I have a functioning ES2 development environment that I want to upgrade to ES4.  I am also moving to a new server (Windows 2008 R2 and SQL 2008 R2).

Currently, I'm running:

JBoss [EAP] 4.2.0.GA_CP01

MS SQL 2005

Java 1.6.0-14

I've read some docs, but am still confused.  I'm assuming out-of-place upgrade, but should I try to Upgrade from ES2 or just do a fresh install then copy GDS and database over?  Also, what configuration files can I copy over (if any)?

Any recommendations or links would be appreciated.

Thanks in advance.