An Optima is simply not the performance car in driving characteristics, or looks (interior or exterior) that the Stinger is. It's just not. In fact, if I stayed in the mainstream mid-size sedan market, I would likely wait another 18 months to see what the next Generation Mazda 6 brings forth. 2018 brings forth the 250hp turbo, but in 18 months Mazda will start showing off the spark-plug-less CCI SkyActiv engine tech, and all-new design...
I really have appreciated my 2014 Mazda, but even the base Stinger, w/Safety Package packs a ton of tech for $34,800 ($2k more for safety tech package).
The Stinger? It's the only player in this class coming around with rear-wheel drive, and it drove amazingly well compared to my Mazda, with a lot of power pointed directly into the wheels to go! Loved the 5 drive modes, and being able to build my own custom mode? Nice touch Kia!
I keep going back to this point: While Buick, Honda, Toyota, Ford, etc... will build a mid-size sedan to pull in as many family buyers as they possibly can, offering all types of engines, stripped down versions to souped up "sport" models, they ALL make massive compromises for enthusiasts.
I've been enthusiast stuck at an economic level that won't allow for a BMW, Audi (boring IMHO), etc... But now? Buick Regal tried and missed. Kia Stinger? Nailed it! Kia didn't compromise the car to broaden its base of sales, cheapening it here or there, give it a non-turbo base engine, etc... Kia stayed focused, targeted true Luxury sports sedans and they came awfully close. And for the money, more than close enough for me!