Preorder Now Presale Timesact

Easy to implement, they can just match most the elements to your theme (easy) and they will set it up together with you with a video meeting immediately after you install. I selected and had it running nicely within 3 hours for a presale. Great customer service, nice people and happy to jump in your site and fix anything. Mostly bugless.
Some nice features, like if you have a mixed preorder and in-stock order, they can do a popup that lets them know it wont ship till the preorder is restocked.