hi regarding accessories kia australia bring the soul 2.0 plus as the top of the range it has half the accessories that are supplied on the north american models and retail price of $10000.00 dearer.
accessories are hard to get because they are standard fittings in other countries, I have purchased some gear from china [ rear camera and monitor with reversing senors] the accessories from the states are cheap and oem but freight kills it. I also required a FULL ALARM system which i thought i was getting, turned out to be a panic alarm only, the sales man only mentioned this after i picked the car up, the same with the bluetooth voice recognition system, it is on the overseas model but not the aussie model. tried many places for the alarm and left the car overnight at 2 professional car security places only to be rang the next day with the words we cannot fit an alarm to this car.finally got it installed by a guy who teaches electronics at tafe.
IF YOU WANT ACCESSORIES YOU WILL HAVE TO LOOK AT CHINA, SOUTH KOREA, ENGLAND AND USA, BE CARE FULL OF DEALER PROMISES AND PRICES.
This info is a bit late but i only just read your post.
If you need anything for your Optima then go to KAI - Koreanautoimports.com.
They are based in the USA and are wonderful to deal with. I have completely re badged my Optima for little cost.
I also had a Hyundai Grandeur that the provided badging and a new grill with bonnet emblem.
There is no better place to buy KIA accessories.