WOD: PreOrder Now

My website is not stocking all products but our warehouse in France has them. We need 2 weeks to get them. In order to not lost the interest, and so the sales, of our clients, I am using this app to give them the opportunity to place orders even if the products are at 0. The fact you can change the name of the button + add info on the item description of the cart page (in my case ' 2-4 weeks delay for this products etc) make the app very flexible. But for me the killer feature is the cart pop up message if you clients are mixing 'pre order' and 'in stock' products in their cart. This is the only app I have seen with this feature. Simple, efficient and you can customize the message too. Mine is saying it is better to place separate orders.
The app was almost plug and play. Just needed a design customization but this is due to my very unique theme. The team has been very efficient. Next step for the app ? why not adding a partial payment option for pre-order ?