I have a 99 mercedes e 320 with a sagging headliner, what kit and how much glue do I need, color is off white...

The headliner kit that will work for the Mercedes e320 would be the small to mid sized kit. There is enough adhesive that comes with the kit to install a headliner in this car. If you want to recover the sunroof slider portion, then you may want to add 1/2 yard of headliner material to your order. It can be added to the cart on the product page.