I just did it a few days ago. Looks more complicated than it is really. Bt it takes some time anyway. You need 12mm and 10mm sockets.
Intake duct is out with 5 bolts: three on left to the intake throttle body (12mm bolts) and 2 on right on top of valve cover.
DIsconnect electric plug to IAC valve; leave IAC valve on body unless you want to clean it, which you can do at any time anyway;
pry collars out and disconnect all rubber hoses. INtake duct is ready to be taken out. Mine came without damage to the gasket.
Remove cable holding clamp for throttle and transmission cables. I disconnected throttle cable from throttle body.
At rear, remove the intake damper (black plastic near firewall: one bolt (10mm) and rubber connector.
Now clean out all foreign material around plug cover and remove 6 10mm bolts.; take out plastic cover.
Now you are in business.
www.geocities.com/lmp4203/kiasport/kiatop.JPG
remove front coil (10mm bolts) :
www.geocities.com/lmp4203/kiasport/kiacoil.JPG
this allows for changing plugs 2 and 3. They are deep under in these holes.
YOu need a spark plug socket with rubber holding device cause the plugs will have to stay in socket to be pulled out. Check for oil on spark plug bases: significant amount would call for more extensive work. Full details for extended procedure
HERE
Some steps suggested on this link are good preventive maintenance.
USE a generous coating of ANTISEIZE COMPOUND - no joke - on new plugs.
www.geocities.com/lmp4203/kiasport/antiseize.JPG
Failure to use it could mean the aluminum threads to come with the plug next time . Just ask for it when buying plugs.
Once done with 2 and 3, (drive with fingers, then drive to seat then 1/6 turn) go for the rear coil and change plugs 1 and 4.
I had to do the job on mine on emergency because it started to sputter and after a few days was finally almost unserviceable, anything more than 1/4 throttle would cause constant backfires and I had to manually switch gears to keep it over 4000 rpm where it could be used somewhat. Code P0302 indicated cylinder 2 misfire.....and this revealed true: look at plug:
www.geocities.com/lmp4203/kiasport/kiaplug2.JPG
it had developped a complete spark bypass and slightly damaged rubber connector too:
www.geocities.com/lmp4203/kiasport/kiaplug2s.JPG
Used a file to scrape connector to clean rubber , installed new plugs and everything is fine now. Will order new cables...