I just bought an expired PR2 domain and it has more than 150 indexed pages on Google, so I am using this plugin to redirect the missing pages: wordpress.org/plugins/404-redirection. It is a good plugin and really works. I am going to create new content especially to backlink my other sites. Now my question is, should I send new sitemap to the webmasters tool or this would delete the indexed pages and hurt the PR? Anyone got experience on this?