Yep - def need to sharpen up you searching as it's been covered many times on the forum. try 'clear indicator' as a search.
In essence the fronts from a prefacelift are a direct bolt in replacement. Facelift cannot be fitted without a lot of other changes.They are seriously expensive if xenon at £740 each from the dealers and rare to find 2nd hand.
The rears are cheaper, but require reprogramming of the LCM or a new module. Very difficult, time consuming and or expensive.
In terms of projects the clear lenses on the front provide a real 'lift', rears are personal choice, but neither seem ideal for you if on a tight budget.