Hi!
My name is Tomasz Kustra, and I am from Poland.
I am interested in this project.
I have experience in gathering data from Amazon, including exactly what you need.
Check my exactly same projects
https://www.freelancer.com/projects/php/Write-some-Software-EDT-11660608/
https://www.freelancer.com/projects/php/Amazon-Competitor-scrape-10086328/
However it does not use API, just web scraping,
But it is able to get more than 1 million products per hour (depending on resources you have)
I am experienced freelancer, you can see my resume on Freelancer.com here:
http://www.freelancer.com/u/tomkusvw.html
As you can see I have successfully completed few similar projects.
I am sure, that you will be glad of my work if you choose me.
With Best Regards
Tomasz Kustra