For many pilots, Piper’s PA-46 series, which includes the Malibu, Mirage and Matrix (and current M300 series), could very we’ll be the ultimate step-up piston single. Get it up high and the airplane can do an honest 200 knots in pressurized comfort (the simpler Matrix is non-pressurized). It’s also a good IFR airplane thanks to sturdy handling that’s more SUV-like than sports car, plus it just looks sexy on the ramp.
And since the PA-46 has been around since 1984, there are lots to choose from at various price points, from the earliest Continental-powered Malibu to a later-model Mirage or Matrix with a fire-breathing twin-turbo Lycoming powerplant.