yeah I think so it's from a build in the USA, The person in question went with a Rieger R-RX front bumper in the end, A bit more detail in the link if your interested.
http://www.cardomain.com/ride/641526/2004-ford-focus/
As you can see below it does look good but on ST170 would look like a normal focus

that puts me off personally.
The other option maybe the front skirt but not very RS like.