Well I would say that for every 4000 tested I get about 150 below 2000ms without the Google test. With the google test that would be 40/4000.
Try searching with the 'last 24hrs' option.
I only harvest proxies, I don't manually find proxies. That would just take too much time for me.
Yes my keyword is [keyword reviews].
And yes, 'stop...fast' is supposed to be a buying keyword. So if someone gets on your site by searching for that keyword they are probably looking to buy but they could also just be looking for information on the subject.
So assuming that they are in a buying mindset, you're presell probably isn't right.
I mean, do you have a review site, or a site with a sales letter or something else?
[edit]
Oh yeah, people will buy something from Amazon faster. One because it is a highly reputable shop. Two because the product have a lot of reviews from real buyers (every review is a presell) and third because the product are tangible goods, digital good still raise some fences when someone is thinking about buying something. (trust issue)