Same here bro, i even think of buying a new door just for the sick of getting that lock door button, perhaps in very near future,we can just add on another button with minimum wiring and with cheap cost..

do ThetaII cars have this feature as well?

Theta II
The Optima K5 features Kia Motors' fuel efficient Theta II 2.0 engine which produces 165bhp and 198Nm of torque and mated to a six-speed automatic transmission that can be manually controlled through paddle shifters.

Combined fuel consumption is rated at only 7.6 litres/100km.

NU Euro4
2013 Kia K5, they are equipped with the new "Nu 2.0 CVVL" engine that replaces the Theta 2.0 MPi engine. The all new "Nu 2.0 CVVL" engine produces 172PS of power and 20.5kg-m of torque. This will provide a maximum fuel economy of 14km/L but if you come with an "IDLE STOP & GO" option, it will achieve 14.8km/L of fuel economy. This is going to be the first Korean-made vehicles to come with a Continuous Variable Valve Lift technology ever to be on sale in South Korea".

Copy and paste from the result that i search from google, hope this will help

Thanks Loh for the figure and stat..

i think i miss out one more diff between ThetaII and NU..

ThetaII = hydraulic steering
NU = electronic steering ?

ａｉｙａ．．but nvm.. i still love my K5.. hehehe..
Thanks Loh for the sharp and correct information