You'll pay about $200 more aftermarket but I think you'll be much more satisfied with the features. On top of the features you'll also get rear climate control with the aftermarket which the factory will automatically downgrade to manual when the sunroof is installed at the factory.
I've have been extremely satisifed with the '01 DXL and the aftermarket sunroof. Also if you can get a 2002 for $500 over factory invoice don't hesitate and place your order, that's a fair price. If you're interested in reading more about the ASC sunroof check out the following link: