SanDiegoFreelance - 8:06 pm on Feb 8, 2012 (gmt 0)
If you are logged into Google and have a Google plus account that you use about the only results you get that are not modified are around two listings. Maps, shares, location, history, google bookmarks, etc, etc all change the results.
Are the serps for the custom search pure? Assuming the custom search does not have a data file that promotes or block certain sites and URLs.