Hello guys and gurus, patulong naman po. i'm planning to buy nissan sentra 03 gx and plan ko rin po ipa upgrade ko ang sound to a better one. my brother is in the middle east kasi and pauwi sya next month kaya balak ko magpabili sa kanya ng player from there as well as amplifier. so,

1. pwede ko po bang kabitan ang car ng any brand of car player like sony xplod, pioneer, jvc, etc?
2. ilan po watts na speaker kelangan para sa rear speakers?
3. ilan din po watts kelangan para sa amplifier and subwoofer?

maraming salamat po in advance for your advices.