I want to change my original speakers in Nissan Maxima 2000, how can I know what size or type speakers I need?

Question

I also want to install a amplifire(I allready bought exreme1200watt), what speakers I need?

Answer 1

6 1/2's in the doors and in the rear deck.  buy a sub and box to use your amp to run and just run some decent priced upgraded door and rear deck speakers just off the deck. you will be happier doing it this way!