reception problems

This might actually be a simple fix. Try this ... did you get a wiring adaptor? Did you cut the Kia radio plug off of the Kia harness? I hope not. If you did not cut the Kia plug off, go get a wiring adaptor for the car if you haven't already got one. The adaptor should have a blue wire in it ... possibly a blue-with-white-stripe wire as well. Hook these blue wires to the new radio's blue wire.

If you have cut the Kia plug off, I agree with DYohn - you'll need access to the factory color codes. Find the wire that is used to turn on the Kia amp and/or the wire that turns on the antenna. According to some technical info that I have,  the factory amp trigger is green and the factory power antenna trigger is grey. Hook these Kia wires to the new radio's blue wire.

Making these connections - even though you have by-passed the Kia amp - may turn on any amplified antenna that is in the car.

Hope this helped ya, man!

Good Luck!