Possible Confused and some recommendations?

Hi Everyone!



I have been lurking here for a while now but after a break finally have another BMW 330 (2003 facelift coupe) to run around in (c:



I was hoping for some help with the age old question of speaker upgrades.



Now I have been doing a lot of research of the options (BSW, aftermarket, amp etc) but would just like to run my plan past the more knowledgeable to see if I am on the right track....



So my current setup is tape headunit with CD changer in boot. Speakers seem standard and I seem to have only 4 + 2 tweeters, is this correct?



I spent ages deciding what to do about the head unit (add ipon control, replace etc. etc.) and have settled on one of the Eonon units as they do everthing and retain a nice oem style look.



So my plan from here is to replace the speakers in my doors and parcel shelf.



I see I can get adapters to fit 13cm (5.25") after market speakers in but am aware I am restricted by depth, but not sure what that depth is?



I would also like to amp all 4 speakers up. So the plan being Eonon -> Amp (through either speaker out put i presume?) -> speakers.



I dont mind running cables and the like but dont want to be cutting my door or anything just want the speakers to fit straight in.



So my questions are this:



1) does this sound right?



2) Do I have to worry about ohm's? How do I know what to get? Do I match speakers to amp ohm'age?



3) What is the depth allowed (or even total sizes) for door speakers with these adapters.



4) Any recommendations for the speakers? Maybe ones that come with tweeters that will fit without too much fuss? (not really wanting the rainbows or bsw's).



Any and all help would be really appreciated!



Many thanks and much love,



Matt