As title, I know NOTHING about ICE, I currently have the standard set up with an iPod interface box plugged into the changer socket...I'm not particularly into subs and big amps and stuff, but is there a good 'first step' to improve sound quality?

I'd rather stick to the OEM HU as it takes my iPod, but the threads about making spacers to fit bigger door speakers scare me somewhat

Havent seen inside a fabia door but in an octavia sound deadening makes a massive difference to the lower range on the front speakers. Not sure if fabias suffer from door water problems but if they do you can buy a moisture guard (second skin) which allows you to remove the plastic water seal from behind the speaker.I have done this to my octavia and it made a huge difference.