Speed up Joomla 2.5 site to less than 2 seconds loading time

We are about to launch a Joomla 2.5 site, and we need some help in speeding it up. 1. Our goal is that each page loads faster than 2 seconds! 2. These are the components we are using: -AcyMailing (from [login to view URL]) -Admin Tools (from [login to view URL]) -Contact Enhanced (from [login to view URL]) -Improved AJAX Login & Register (from [login to view URL]) -MijoACL (from [login to view URL]) -MijoSearch (from [login to view URL]) -MijoSEF (from [login to view URL]) -MijoShop with Opencart (from [login to view URL]) -Yootheme Widgetkit (from [login to view URL]) -Yootheme Zoo CCK (from [login to view URL]) -Yootheme Infinite Template (from [login to view URL], adapted with [login to view URL]) -A custom component that acts as a bridge between Zoo and Opencart -Joomla backend tools from [login to view URL] and [login to view URL] 3. These are our requirements: -Preferably no changes to core files -That it will be possibility to update the components above in the future + documentation of post-work (if any) that has to be done when updating components. -Documentation of the work 4. A part of the work is to find bottlenecks, conflicting scripts or errors on the site, and to fix them. And to suggest changes that we can do to images or other content. 5. We will provide a full backup of the site, so that you can work locally. We can also provide a test area on our host, for live testing. To get the URL to our current test site, please contact me. Also contact me if anything is unclear or if you need additional information.