WebDir can be evaluated in a lab, virtual machine or in a live environment. WebDir is very light on the enterprise and does not "dig" into Active Directory. The only changes to Active Directory are the specification of a service account and two groups to define who will have Helpdesk and Administrators permissions within WebDir. We recommend that you create new accounts and groups for WebDir so you can manage the security exactly as you'd like, but you are welcome to use existing accounts and groups.
Most of our customers do evaluate new products, including WebDir, in a lab or virtual machine as a best practice.
Hope that helps. Feel free to email me offline if you have specific questions or if you would like a copy of our WebDir Reviewer's Guide.
Marya Gomez
Imanami Corporation