Hey guys. I'm Nick, I work over at a place called ModBargains in La Habra, but live in Anaheim.
First and foremost, I am an ST owner myself and this is my personal account, and I'm not a salesperson, so you can't order thru me. But where I work we do a LOT of business with Forgestar, so I know a thing or two on the topic.
Edit: So, I spoke to our reps that directly interact with Forgestar, and I'm told they can only do 5-lug bolt patterns. Which means that while they can do 5x108mm for Focus ST they don't do Fiesta ST.
You can get wheels from Forgestar at ModBargains.com or at our location on Lambert Rd in La Habra. You can use the website to chat with one of the actual sales guys about the wheels themselves (or call 714-582-3330 if you prefer telephone) as they know more about what exactly Forgestar can and can't do, but based on what I've been told Forgestar can't do 4-lug.
HOWEVER,
that said, I do know that the ESM-004 wheels I sell DO fit Fiesta ST. They're available in 17", 4x108mm ET 35
http://www.modbargains.com/esm-wheels-esm-004-17inch.htm
Related: my pshop of my car on ESM-004s (I was considering a set)
Cheers,
Nick aka Blue Bomber
'14 PB FiST - stock... but not for long