I am not a Kia expert. But, I caution against immediately cutting the body to achieve clearance.

A basic lift is dome with springs. Okay, you can add spacer blocks. But, where you add the spacer can mean a lot.

Welding the front diff... that brings up the Lincoln Locker discussion.

As a matter of disclosure, I have driven a fair number of miles in a Jeeper with a welded rear end.

That said, you would be foolish to weld the front diff. Basically, that is your steering component and welding will induce steering ability in standard (non-OHV) driving.

There is a discussion thread dealing with the various TJ springs than can be adapted to fit a Kia.