I don't think there is any need to download from the site if you haven't deleted the downloads from your command center download path. Depending on when you last (if ever) cleared that directory out, you should have all the recent versions of Sonar installers already on your machine, but if you have cleared it out at some stage, you may be missing other stuff such as plugins etc. that haven't been updated/downloaded since you last cleared it out. All installers should already be on your machine, you may need to grab the product keys from your account.