Expect it to be impaired, because distilled water will not absorb into the soil as effectively

Expect it to be improved, because distilled water is less variable from sample to sample.

Performance will be unaffected because the soil itself determines the conductivity, not the water.

Expect it to be impaired because distilled water doesn't have dispersed ions, which limits its ability to conduct electricity

Expect it to be improved, because distilled water is purer and will provide a cleaner, more reliable reading.