Original Automotive Related Blog Articles

I require writers to compose blog articles for my automotive review site. The articles need to be at lest 80% original. I currently have automotive make and model related topics that I require 2 article per month for each. For example one of the topics is the Subaru BR-Z. Within the next 2 months the number of topics will grow to over 150. Each article will need to be original and relevant to the make and model of the car and be a minimum of 300 words. All the sites are car make related meaning the article needs to be related to that car make and model. There will also need to be an image sourced from the web for each article. The chosen writers will be given Author access to my Wordpress site to submit the articles. Please list how many articles you will guarantee for USD50 and in what time frame. NOTE: NO CONTENT SPINNING