Give the bloke/lady a chance
...all of that is perfectly explainable with some certain assumptions:
illuminated door sills - Genuine Alfa option on the 159, I guess you want the same for the 156?
small spoiler possibly - Like the original Alfa one? I had one on my last facelift car...and that was about the only negative about the car....though I still seriously miss the car as a whole!! - Ebay (See attached for a pic - you can just about see the spoiler)
crystal side repeaters - You mean clear ones? not bling bling crystals? Loads on ebay
leather interior - Ebay or Autolusso or local breakers
subwoofer - Like the Bose original equipment one? -ebay
CD changer - Why not get an mp3 player? but if so get one from a scrapped car via ebay/Autolusso/scrapper
alarm which makes a sound when locking or unlocking - your standard one should been twice when unlocking and once when locking, its possible you have disabled the key sound via a combination of button presses, check the manual
red calipers (with alfa romeo painted on) - no point replacing the calipers, so assuming you want some like the ones that came as standard on the Alfa GTV V6, these are in fact just painted red, then a sticker applied with the Alfa logo, then lacquered over.
