COOPERATION: Speed up wordpress / joomla websites!

Hello, We are a software development firm, we are looking for experience developers for a long term cooperation to be able to: 1) for any website with wordpress \ joomla. 1) do initial "Before" speed test report 2) improve speed in websites - in at least 30%. 3) do the "After" report - and prove that speed wast actually improved. 4) if not improved by at least 30% - 100% money back to the client. * Fixes will not include CDN \ hosting change (these are services we provide) * In some extreme cases - with a good explanation - developer can refuse to work on client site \ ask for additional fees. The price must be fixed for the project as follows: a) one time X $ for making the site faster. b) monthly Y $ for a monthly report and improvements if possible. We are able to bring few hundreds of clients in the next few months - so we are looking for a good service and in good prices. - please bid with the X price for the one time cost. - please show us explicit portfolio \ experience in speeding site up. thanks