As with anything, the phrase "it depends" applies. Which car, which gun and what condition the bolts/nuts are in. Best case is a passenger car, properly torqued to 80-100 ft-lbs and rotated regularly (bolts aren't siezed in with rust), a cordless impact gun should have no trouble at all with them. Anything rated for 200-300 ft-lbs should do it nicely (you could probably get away with something that was rated as low as 170-180). On the other end is something like a work truck where the torque spec is closer to 150, they haven't been removed since the last time the tires were changed and it lives in the rust belt. Expect that to give a 300 ft-lbs wrench a run for it's money. 10 seconds of rattling may get each bolt off...or not.
The tires on my cars are swapped 2x's a year and I don't remember the last time I broke out the air gun. It's either the cordless impact or in one case, a 2ft breaker with a 2ft cheater thanks to a careless tech. I have a 3/8" milwaukee fuel that I haven't been impressed with (sometimes takes 5-10 seconds of rattling on a nut before it breaks loose). But their mid-torque wrench has enough extra power to tackle all but the most stubborn lug nuts. It zips off the bolts on my cars without hesitation, but I don't have a rusty work truck to test it on. They have bigger impact wrenches, but the added size and weight make them impractical for suspension work and they are really inconvenient.