230V impact wrench or a rattler

I know there are already some threads, but I don’t get smart from them because everyone says something else. I need a impact screwdriver to solve really hard screws under the car. For example, where you can’t get to bad and exercise real power. If you were to spend around 500€, now my question is whether it’s better to invest in a good 230v impact screwdriver or rather buy a small compressor with Rattermann. Thank you for your help.