Dudes, need some help here.

Budget: RM400-600
Type of song: Chinese pop, RnB, English Pop
Preference: Sound Clarity

Right now I'm driving a Satria GTi, both left speakers (front and rear) are spoilt. Damn annoying scraping sound when the bass kicks in from certain songs. I just changed a Kenwood HU, and now planning to change all the speakers.

What is your recommendation? Do I need to get an amp? Or just get 4 speakers + 2 tweaters will do?

Sorry for the noob question - I did a search in the forum but didn't find any threads that could answer my question. Thanks!