How much torque do I really need in a cordless impact wrench for automotive work?

For passenger-car lug nuts (typically torqued 80-100 ft-lbs) and most suspension work, a mid-torque impact rated around 400-700 ft-lbs of fastening torque is plenty. Stuck axle nuts, rusted exhaust bolts, and truck/RV lug nuts are where 900+ ft-lb high-torque models earn their keep. Specialist-community threads consistently note that real-world dyno numbers are often 30-50% lower than marketing claims, so don't shop on the headline figure alone.