new to mazda 3 but not mazdas or mazdas 24/7 have questions on exact speaker fitment

as the the title says i have been a mazdas24/7 member for 2 years now and had a protege5 that recently got totaled. i have just purchased a 2008 3 hatchback i see it uses the same 5x7 speakers but i was wondering if anyone knows if Rockford fosgate punch 6x8s will fit depth wise as the motor on the back looks fairly large if not will jbl 6x7/6x8 fit fine? also i have an aftermarket headunit and 4 channel amp and sub with separate amp i will be installing anything i need to know about this car thats different/more difficult from the protege other than the steering wheel buttons?