Theta II engines are already found on Sonatas and Optimas around the world. They were introduced in both the facelift Optima and Sonata. Another feature incorporated is the Variable Induction System. A new 5-speed gearbox was also introduced with the Theta II engine. We don't get both facelifts in Malaysia hence we don't see the Theta II.
About Theta II, rethink about Rondo, I remember they did mention that its engine is THETA II not THeta I4. If that's the case, the difference found on the intake manifold compared to Theta I4 in Optima/Sonata. No dual CVVT, just intake site only.
SIME, Kah Bintang & Naza purposely refuse to bring in the facelift Sonata & Optima. Reason is the Sonata & Optima sales quite low. Why waste money to bring in facelift variant if many dislike it. Most marketing people will think that maybe they dislike the looks. They didn't notice that if they could reveal to every1 that the entire technical is Japanese Mitsu especially 4B11 rebadged Theta engine, people will go for it. Too bad, Koreans ego is more important than sales.
They are waiting for newer replacement instead as the public might like the new 2010 Sonata/Optima design. More hope compared to facelift Sonata. The big jaw dropping grill in facelift 08 Sonata is quite irritating. Optima/Magentis 08, it is sold only in the US just like Cerato facelift '07. Not available in any other country including Australia, Singaland, Thailand, India, HK, Taiwan, etc.