I've driven all 3 and owned a W204for a few years. I'd pick the 4L C63S and scratch the V8 itch. The W204 has an amazing engine, it was totally faultless for my 3 year period of ownership. B road blasts on a cold Sunday morning were epic but the rest of the car would show it's age in 2015 nevermind 2025. The gearbox, lack of rear LSD meant its extremely twitchy and the rear is too lively when you're giving it the beans. The interior is not only too dated by today's standards but a fair amount of random creaks and squeaks. The W205 C63 is a much nicer place to be but definitely doesn't have the 6.2L character.