Scrap yards will be come your best friend i found a ghia and got the variable wiper stalk, door handles, front footwell lights and heated seat wiring loom for 15 quid.
Get yourself some "projector" lense angel eyes for the proper ford oem xenon headlight look, usa spec rear lights with the clear indicator lenses too also try find a dimming interior switch if u can find one.
Ghia map lights are good too and cheap
Interior trip computers are a majour faf but if you have the time theres a guide and a few threads on here with how to do's
The leather seats are ace just need to check the hair bags havent gone off in them though and check what model there out of ghia seats have pretty much noside support so if you want to drive your focus properly check there out of a zetec or edge etc
Rs's are pretty basic in truth they have next to no luxury just air con and ace seats