Hi there !
I am very interested in your project and, after reviewing your brief and looking on Unique Mechanics website I can say that this task is perfect for me.
Similar websites were completed by me in the past, including the eBay link to the backend. So I am about to suggest you starting over Opencart platform, which fits perfect with all described above, it is reliable and easy to work with (very helpful admin panel)
We can have any design you wish, even like the example website and all features will be there, like shipping, payment methods, checkout config, etc.
Timeframe will be 10 days as I already bidded. I work alone and very fast, no outsource like indian people do.
If you pick me for this project, I will also give you some SEO services for free, so your new store will get indexed in Google very well.
There are many things to say but the best will be in a private discussion, I don't want you to be swamped with a huge proposal.
Hope I can hear from you soon and we can work together.
All the bests,
Adrian