Generally speaking,,,,,,, 5W-20 is an excellent choice for this engine. The service manuals even suggest it with 5W-30 generally being a second choice.
http://www.kia-forums.com/do-yoursel...e-manuals.html
Finally,
If you're using a conventional oil where you'd probably change oil twice a year or more. Use 5W-30 for the summer if you're worried and 5W-20 for the winter. Simple to schedule.
To be frank the 5W-20 myths are unfounded. Cold start protection is key.