The Impala nameplate spans six decades and two entirely different missions: the '60s SS models are among the most beautiful American cars ever built, while the modern FWD sedan is a spacious, comfortable highway cruiser with a ticking clock under the hood. That clock is the 4T65e transmission, which fails with enough consistency that police fleets, high-mileage civilian owners, and forum threads all independently name it as the car's Achilles' heel, often giving out between 150k and 220k miles. If you're restoring a classic, you're buying into a legend with straightforward mechanicals and endless parts support. If you're shopping the 2000s-era FWD generations, budget for a transmission rebuild and you'll likely get your money's worth.
The Mazda3 is what happens when a compact car decides it's too good for its price bracket, and the interior actually backs it up. The 2.5L engine is bulletproof (owners routinely see 200k+ miles), but the 2019 redesign swapped the old multilink rear suspension for a cost-cutting torsion beam that blunts the handling sharpness earlier models were loved for. If you want a refined daily driver that feels expensive and runs forever, this works; if you want the sporty Mazda everyone raves about, hunt down a 2014, 2018 instead.