Today his aesthetic leans heavily on proportions and clean surfaces. He prides himself on "no gimmicks" and takes umbrage when the Optima's decorative side vents are noted. "That's a detail that helps the proportions to look a bit more like the classic proportion of cars," he said.
Schreyer makes monthly trips to Seoul for regular meetings with the heads of Kia's South Korean and U.S. design studios. Mediating culture gaps remains a challenge.
When a problem crops up, Germans wade in to tackle it head on, he said. Not so in Korea.
"We have a problem here or there, who can I talk to? Who can make the final decision or help to make the decision or help to get this problem done somehow? It's like biting into cotton candy; it's gone," Schreyer said. "There's no one there you can get ahold of."
But once a decision is made, Schreyer said, Koreans are lightning fast at putting it into action.
"We do a clay model, and after we give a presentation and do the model fix, a few months later we see a perfect prototype," Schreyer said. "It's amazing how fast they do that."
Schreyer reckons the process takes a year longer at VW-Audi.
The German design chief -- with his signature black clothing and thick-rimmed eyeglasses -- sometimes bumps heads with the conservative styling sense deeply rooted in a Korean boardroom that long valued safe, if boring, designs. But no one questions his mission.
"The expectations are very high to really make a change and make something different," Schreyer said. "This is why they wanted me."
Schreyer's arrival dovetailed with other improvements at Kia, such as better engineering and improved quality. But making his design overhaul stick will be the tough part, said Imre Molnar, an auto design critic and dean of the College of Creative Studies in Detroit.
Molnar cited BMW's Chris Bangle as a designer whose influence endured after he left. Will Schreyer's imprint on Kia be as lasting?
"He's made his mark with the work he's done there," Molnar said. "But going the distance will be part of it. Maintaining consistency is what will solidify his legacy."
If sales are any indication, his designs have clicked with the public.
Kia's U.S. sales climbed 37 percent to 104,774 units in the first three months of the year. That outpaced the overall market's 20 percent surge and the 28 percent increase at its South Korean sibling Hyundai. Market share advanced to 3.4 percent, from 3.0 a year earlier.
"Our competitors are Volkswagen, Opel, Nissan, Honda and Toyota," Schreyer said of Kia's heightened sights. "This is what I'm thinking about: how to position Kia in that world."
While enthusing about memorable cars, Schreyer cited another collector's item in his personal garage, a Fiat Spider Volumex by Pininfarina -- a car that, in his words, "I will never sell."
He aspires to invoke the same reverence for Kia: "I'm waiting for the day there's a Kia you never want to sell."
That won't happen overnight. Schreyer is still completing the current lineup's overhaul with the Rondo and Sedona, starting next year. But the next generation may open new doors.
"What we need, and what I would like to do, is some sort of roadster or convertible," Schreyer pledges. "I won't give up until we have one."