Noise when turning Steering wheel and Knocking. What could it be?

It could be many things, unfortunately and without hearing the noise first hand or being able to do some basic diagnostic tests or be able to drive the car, its hard to say what the source of the noise may be. Kia as a car manufacturer put a lot of great technical information and work shop manuals on line for free for Kia owners. www.kiatechinfo.com Not sure by your description if the noise is a bad CV joint or a steering pressure issue.

I agree with Patrick on this one. there are so many components that could be causing your noise that the best thing to do is make an appointment with a shop you trust and let them give it a good inspection. Could be ball joints, tie rod ends, steering linkage, etc... Bring this one in for a professional opinion.

it could be shocks or struts going out about 425 when done replacing both sides