Great guide.
I wouldnt bother upgrading the side lights to LED's. As you say you wouldnt need sidelights on anyway if you have DRL's. Except maybe to comply with local laws or technical testing/mot.
Maybe a pedantic person (police or technical tester) might insist the DRL's s are not bright enough, or correctly positioned to qualify as DRL's. If, as is the case in Bulgaria, its compulsory in Greece to drive with headights on if you have no DRL's, upgraded sidelights still wouldnt help.