Are you positive it is the front ones? Usually the rear ones go first.
You will need to remove the entire hub assembly and remove the old/install the new with a press.
The "storage" lubricant which comes with the bearings must be absolutely, positively cleaned out and replaced with the highest quality bearing grease. The hub must then be torqued to the recommended setting.
Also, refer to this site
http://www.subarusvx.com/faq.html
Matt