This kit is designed for the 16-18 Ford Focus RS and is not compatible with the Focus ST. It is designed to replace the OEM fuel filter which is plumbed between the electric and mechanical fuel pump. The Radium kit installs in minutes. No cutting or drilling is required. A couple of wrenches is all that is needed. 

Because the Radium filter is less restrictive than the OEM Ford filter, there is less stress put on the fuel pump (3-5.5psi less). Lower pre filter pressures will permit less current draw and thus less fuel temperature. Furthermore, this phenomenon permits an increase in fuel flow. The red marks below represent one aftermarket pump and the purple marks denote 2 aftermarket pumps. Note that there is a 2% and 4.5% flow increase, respectively.