Having had costly replacement of secondary air valves and pump ( south of £1800) on my 2008 FORESTER XT  50k (reg. Dec. 2008) one poster suggested there had been a mod. after 2007 to avoid this condensation damage. Local dealer reckoned car manufactured early 2008 so why the fault ? Nor could he confirm that the replacement units were "modified" . Checking with SUBARU UK  HO it turns out the car was manufactured in 2007 and they are not aware of any mods. 

wow that is not very confidence inspiring