speakers, 99 grand marquis

99 Grand Marquis has no rear door speakers. Should I change out all the factory speakers with components or put comps in front doors and 4 6.5 or 6x9 coaxals in rear deck. Or put 4 6.5 comps in rear deck.(The Great)

Its said that comps should only be used on the front stage. Everything else can be coax, 2/3/4 way. Id rock 6x9's anywhere you can anytime you can. If you got subs in the trunk, the back dash speakers will need enclosures. In my prelude even with the back seat down, the subs caused air pressure to distort the rear deck speakers. I eventually took them out to make ports.This is what I do for FUN!