recommend some speaker upgrades?

Hi guys ,

I'd like to upgrade the speakers in my 2005 318Ci , the factory ones aren't up to much.

I've always gone with pioneer in the past and have been very happy too.

My questions are:

1) the door speakers, do i need components or will a 2 way speaker work with the top end component that's already in the upper door?

2) the size of the speakers in the lower door should be 6.5" ? right? I'm aware that a mounting bracket will be needed for this.

3) the rear parcel shelf speakers, will the 6.5" speakers fit here too ? (with the use of a bracket)

4) are 6x9 speakers out of the question for the rear?

all help greatly appreciated