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Sitemaps won't affect your SERP greatly, but it will help to speed up the crawling process on your website. I'm not sure why you have sitemap for only 1 category. For the sake of completeness, why not just have sitemaps for the entire site? Its not that hard to set up a sitemap.

If you're not tagging your destination URLs in Adwords, you will need to turn on auto-tagging so that Google Analytics can track clicks from Adwords.  When you log into Adwords, click on the "My Account" tab, and choose "Preferences".  If auto-tagging is not enabled, enable it.  What this will do is when someone clicks on an ad to your site, you'll see a parameter added, called gclid.  This parameter encodes all the data that you'd normally have in your utm parameters (if you build URLs like these from here), so that Google Analytics can properly track your ad campaigns. Also, like Chris mentions, make sure in the admin settings in Google Analytics that your account is linked to that Adwords account.

Hi Hamid Is FDFPres' answer helpful? I am not a Meganto expert, but can find another associate to help if you need it. Also, after you update the URL's you might have to do 301 redirects from the old ones to the new ones if Magento does not do this automatically. You can see Moz's resource for more info: http://moz.com/learn/seo/redirection -Dan

just leave it. Double check for errors on it.