Swifts/Extreme Motorsport in Whitburn, West Lothian - 2 minutes from Junction 4 of the M8. They will do the work for you - they have their own, best quality new 4 wheel alignment gear, are Subaru and Mitsubishi specialists and are "doing up" their premises at the moment.
Used by me and many others to do work such as oil changes, they are Whiteline authorised dealers etc.
Brian