^^ bitin yang 20k chief, kung gusto mo ng may BOOM effect at least 30k.
Invest on a good head unit mga 7k up pioneer or alpine would be a good start
as for speakers 3:1 dapat budget split mo (ex. 6k front stage, 2k rear fill)
subwoofers at least 5k para medyo decent sounding naman
amplifying the sub is a must so mga at least 5k ulit
wiring and labor cost mo 5-10k din = approx. P35,000 in hand for basic sound system