hoping to replace sink and shower/tub faucets

I currently have Kohler tub and sink faucets. Does anyone know if I can buy faucets of another brand and swap them out with the old ones without changing any of the plumbing in the wall of the shower or do I need to stick to the same brand? Thanks.

faucet

Some faucet companies supply their "in the wall" portions to other companies so that they can be "upgraded" with custom trim parts. Kohler is NOT one of them, so you either use new Kohler parts that FIT your valve, and that means only certain faucets are suitable, or change the entire unit.