Did it really need a new motor? My dad's hydrolocked his old blazer driving across a creek and I've hydrolocked my old sebring (clogged drain on the interstate) No CAI in either of these. But anyhow, we were able to get both of these vehicles running again with no issues. We took the spark plugs out, turn the motor a good bit to get any water out of the cylinders, changed all the fluids for good measure to make sure there was no water there. Hydrolock doesn't automatically mean "new motor".
typically it means piston through side of block. not always though, you are correct.
main thing is that if you do stall in water, TURN OFF YOUR CAR AND DO NOT TRY TO RESTART IT!
you will need to do as mordant80 says and replace the plugs, change the oil, etc.