100k? Naku ang dami nang magagawa dyan. I agree with baiskee, punta ka na sa kotseaudioclub, maraming tutulong sa'yo dun.
Advice ko lang just make sure you understand what you're doing muna bago ipakabit. I remember when I started making inquiries, gusto ko mas magandang speakers lang para mas may bass. Ended up na nagpasetup na ng amp, seps and sub around end of June. At ngayon, nagiisip na ko kung pano ko pa papalakasin hehe.
Understand what you're doing and audition systems. Check mo rin 'tong link na'to, marami kang matututunan