Good day sirs! Need help and your expert opinion.

I want to setup my montero glv with stock head unit.
my budget is around 15k to 20k
Habol ko lang is sound quality. Hope you can give me suggestions as to what kind and specs of speaker I need to buy or Saan ako pwede Pumunta for my beginner set up .

Medyo excited na ko magkaroon ng good quality sound . Sarap kasi basahin mga audio setup thread dito kaya ako naenganyo.

salamat po sa advise.
More power!