still make decent power when not under boost - it just wont be anything to write home about. The displacement of the engine will still be the same so the turbine will be getting good flow for spoolup. Using a spoolup NOS setup would be the way to go and you could make your power curve much more drivable. But relying solely on turbos to do the job under the hypothetical that you defined would not be a whole lot of fun. N2O spoolup would make it very nice and usable.