No. Meta keywords and meta description haven't got any effect on rankings. Only changing Meta description could boost your CTR.
That is an incorrect statement. Changing your meta description will have an affect on your ranking. The best thing to do is leave the main keyword in the description but change some of the other wording around, doing this will also help get your site recached.
I find it best to setup like this .. TITLE: Site_Name > folder > subfolder > subsubfolder: cat1, cat2, cat3, cat 4 .. META DESC: one sentence describing this page using keywords at least once. (Dont use just keywords or your exact title text.) META TAGS: subsubfolder, cat1, cat2, cat3, cat4 .. hope that makes sense ..
I wrote an article on that a while ago - don't mind the title... http://www.katinkahesselink.net/internet/meta-tags.html
False We change Meta Tags Keywords/Descriptions/Title for improvement in the results and to have its own uniqueness
meta tags keywords/descriptions/title will improve your rankings if your major keywords are intregrated in your content. Other important factors: - Content - Related backlinks with anchors