Why would you have to have UD pullies? That defeats the purpose of the whole supercharger application. Everything will be spinning slower because of the UDs, including the supercharger. Go look on the 4.6L board, or 5.0L board, and see if anyone is running UD pullies with a supercharger....NO ONE is. Yea, it's a great mod if you stay N/A, but once you go supercharged, you have to take them off.
Or if you were going turbo, then you could leave them on, since a turbo isn't belt driven, but it won't work for a supercharged application.