Kimi Raikkonen is hopeful that Lotus will be able to step it up in Korea on Saturday after struggling during practice on Friday.
The Enstone squad have followed in the footsteps of McLaren and Mercedes by introducing a new exhaust system, which harnesses the Coanda aerodynamic effect in an effort to boost rear grip.
The new package was given its debut at Yeongam during the first two practice sessions, but Raikkonen admits it was a bit of a struggle.
"I think it's too early still. We'll look at all the data and see how it is," the Finn said.
"We probably expect a bit more than what we've seen so far, but it's too early to say."
He added: "It's not very easy to get the car right. Hopefully tomorrow will be better."
After posting the 11th best time in the first session, the Finn managed to move up one place in the afternoon but Lotus were still well off the pace of the front-runners.
Raikkonen, however, feels there is plenty of room for improvement before race day.
"I think we are more or less where we usually are on Fridays. Hopefully we can improve the car and be faster tomorrow," he said.
"The car didn't feel good today and we were one second off the pace, so if we can it right we can get higher, but other people might improve."