Hi Al its easy you buy the unit online (put a search in for Superchips Bluefin). Buy the Bluefin unit and plug it into your diagnostic port , it then reads your ECU.
After that you install the Bluefin cd into your computer , then plug the bluefin into a usb port and it uploads the info to the superchips server.
After superchips get this info they remap the info you have sent them and then once this is done they will mail and text you telling you to plug your Bluefin unit back into your computer and download the remap.
Once you do this you plug Bluefin back into diagnostic port in your car and the bluefin unit will load the remap to your car.
The good thing about it is you can use the bluefin unit to revert you car back to standard also
Direct from superchips it costs £435
This is the link
http://www.mybluefin.co.uk/index.php?option=com_content&task=view&id=34&Itemid=82