I have ford figo aspire.
Also having the below parts.
1) Infinity component speaker 50.11CS
2) Infinity reference speaker 5002IX
3) Hertz he4 amp
4) LOC converter.

My question is, i would like to retain stock HU(2017 model.not touch screen).
suggest me on best option.

Option 1 : Front component and sony 1800w subwoofer into amp and Rear speaker to be stock speaker.
Option 2 : Front component and sony 1800w subwoofer into amp and Rear speaker to be infinity reference speaker.
Option 3 : All 4 speakers alone in amp.(no sub).

Kindly suggest me the best option.