not sure on price for a ka24de, you'd have to ring around, but if the mounts did match, then i think that it would be the best non turbo option available, other than that the ca18 would be your next best option. then there are the rb series of engines which you can swap in. i think the most difficult to swap in regards to custom work/mounts needing to be made would be the sr20 an fj20.
also remember that it is illegal to install an engine that is older than the car itself, so that might rule out the fj20 all together.