I know that almost every sonata mod has been discussed ad nauseum in this forum, but I've yet to see a complete dust-free mod for the sonata.
So nothing illustrated here is original, it's just a collection of mods found on SPCR, which should rid your sonata of dust for good (although I may reserve judgement on that until a few weeks have passed).
First - block those stupid antec holes:
Block up any unnecessary holes inside the front bezel i.e. the gaps behind the front ports, with some sound insulating foam (I placed a few offcuts around the front bezel for some minor minor damping). If you happen to be less lazy than myself, you could cut more of the inner bezel than I have.
The ubiquitous sonata bezel mod:
Now to rectify antec's air-filter mischief - take some open-cell foam of an appropriate thickness:
Cut it to size...
...and place it inside the filter insert. I also added some more neoprene foam onto the botton of the insert to block the tiny gaps aound the filter cage:
Now for some more foam around the edge of the door. Cut it just thick enough so that you feel some pressure when you close the door, and so that the door clips shut.
All these together should stop any dust building up around the optical drives and ensure that all air entering the case flows through the air-filter first:
Finally, throw away those pathetic rubber coins antec provides and add some nice thick rubber feet to the corners of the case:
Neoprene foam - £6
Open-cell foam - £4
Feet - £4
Time - ?? long enough to piss me off that antec didn't bother with this stuff in the first place....