since my car is a lease and i will be turnin it in soon could i just add like 2 6x9's or some other speakers and put them in there own box.

so i would have my own speakers that came with the car and those added off another amp.

basically my 1 10'' l5 is too loud for my stock speakers and i want to upgrade to 1-2 12'' type r's off 800ish each.

and i know i wont hear the music with those