Help needed - Non BSW speaker & Amp Upgrade

[cooa99]

I am planing to retrofit folding mirror, and just thought I might as well upgrade the speakers as well.
BMW X5 is E53 2005 16:9 Monitor with MKIV navigation & without DSP & Amp.

I noticed that the front doors by rear view wing mirrors have perforated Tweeter like enclosures but no sound comming from them. Is it safe to assume that only the High spec Audio/comms package have additional speakers/tweeters in this location. I currently have 2 dash board, 2 Front door and 2 rear door speakers.
The BSW kits are way higher than i want to spent so enough said on that.
1) Any one fitted other brands of speakers in the door pods? e.g pioneer/Kenwood/sony/ alpine... If so what sizes/models? and do they need mounting adapters?.
2) I have asked this question a few time without an answer, since my car has no Amp, How do i connect an Amp ?. Any literature on this would be highly appreciated
Thanks very much

cooa99