Keyword Research w/ Compaeition Levels: Question I need answered

I picked a niche I could build a large amazon affiliate site around. Im talking 50 items with in this product grouping.

This is my problem.

keyword
best keyword
keyword review
keyword model number
keyword model number review

They all have amazon on the first page. In fact, looking at the keywords, all ranking sites have a high DA, but a relatively low to moderate PA. Is it possible to compete on a PA basis? Is it possible to compete with amazon sites ranking?

Seems every niche I google has amazon sites or ebay ranking.

Thanks

Remember a couple of things:
1) It isn't all that difficult to outrank Amazon/eBay particularly if you have an EMD for that product. Have a solid backlinking plan, and make sure your onpage SEO is spot on.

2) If every niche you're looking in has eBay/Amazon vendors which are performing well it's a pretty good indication that you are looking in the right areas. It's important to have these types of websites in niches where you can clearly see that people are performing well and making good coin. The last thing you want is to put time and money into ranking page one, only to realise nobody actually wants to purchase that product or that consumers in that industry are only after free products.

It is difficult to outrank any "authority" site.especially ebay and amazon,which are highly popular.I never say its impossible ,but it takes a huge amount of hard work.Optimize your site better than your competitors with more content about the topic, and build links the best you can to compete with amazon.start you hard work from there.you will see its paying off later on.