For Stage rally you have a couple of choices. DMS, HotBits, RS&SP, Pro-Flex:
HotBits are the cheapest and Simonac has started running them on his Spec Focus. He said they held up well at Rally NY. Check out: http://www.davenportracingusa.com/
as he is hotbits dealer.
DMS are expensive. They are a good strut until they break. The fronts are particularly weak where they bolt into the knuckle. The spec focus rally cars have broken 4 struts like this in the last 2 years or racing. That being said they soak up the bumps and rough stuff at speed and make the car really easy to drive.
RS&SP: Is kinda an unknown. The Subaru / EVO guys rave about them but no one has run them on a focus where in the states. They are around $1,000 more expensive than the DMS but are 4 way adjustable.
Pro-Flex: They were a popular option in Europe. They use an off-set front strut hosing which allows you to run stock wheels more easily. Not sure on pricing or a US dealer.
You can also check out http://www.rallyanarchy.com
. There is a guy there that builds custom rally suspension for pretty much every car, he might be able to set you up with something.