@abid110
Abid bhai, I think your denter has quoted reasonable in fact Very reasonable Quote because your job is : Bumper Readjustment + coloring + Fender repair +Bonnet adjustment
However Light of 400 seems Little High.I think you r referring to Original one(Taiwan or Koito)
NO NO DO NOT FIT BLACK BUMPER,IT WILL RUIN ALL BEAUTY. Get it color matching bumper.
VOLTAGE STABILIZER is just like you are using for your Fridge/LED in your home. With passage of time, resistance increases in electrical wires, similarly Quality lessen with Age, Also Ground Quality is sometimes not effective so all such cases causes Voltage Fluctuation.Most of your devices need 12.0 V so up/down voltage damages your components.
Voltage Stabilizer increases the life of your Alternator.
I have experienced Duet's ac in various cars of my friends. Mitsu compressor becomes useless above 35. They are not designed for such cabin for such climate.
I have not experienced your car's cooling myself so i cannot judge but u can answer yourself that is it cooling worth? or time to change