hi,
you first have to remove the existing one.
you will got the diameter you can use and see how deep they are and see also if you have room for fit better (the deeper the better)
for listen separate tweeter you need a full set with filter , same for the subwoofer.
you can notice the different if you pocket is really deep , a normal sound system with just 2 way speaker is not the story as a complete sono with active or passive speaker and from one to several amplifier.
my opinion is a good alpine and 4 decent speaker will do the job you expect , unless you are die hard top sound listener.
PS: i have instal top sono in cars for 7 years ...
