Put yourself in Google's position, would you consider the most important site the one with hundreds of links from the same domain/IP or the one with hundreds of links from hundreds of different domains and IPs. I am not saying your interlinking tactics doesn't help but it is not hard to beat and at the end SEO is basically a competition
For the second part: if you are talking about keywords meta tag, the general opinion for a quite long time now is that SEs doesn't take this tag into a consideration at all.