It's been nearly four years since the second-generation Porsche Panamera debuted and now it's time for the entire lineup to receive a mid-life refresh. And leave it to Porsche for those updates to be extensive. The 2021 Porsche Panamera sedan and Sport Turismo body styles feature several design changes as well as powertrain improvements. Let's start at the top.

The Panamera Turbo is now the Panamera Turbo S, powered by an uprated 4.0-liter twin-turbo V8 now making 620 horsepower and 604 lb-ft of torque instead of the previous 550 hp and 567 lb-ft. Improvements to the crankshaft, connecting rods, and torsional vibration dampers are among the changes. There are also new fuel injectors.

Porsche claims a 0-60 mph time of 2.9 seconds with Launch Control, a 0.5-second improvement over the outgoing Turbo. Top speed is 196 mph.

The Panamera GTS (pictured below in Sport Turismo guise with red paint) also returns with a 20 hp increase, now rated at 473 hp and 457 lb-ft. Not unexpectedly, Porsche is placing significant attention to its hybrids, offering a new trim in the form of the 4S E-Hybrid (pictured in white). It comes powered by a 2.9-liter twin-turbo V6 connected to an electric motor for a combined output of 552 hp and 553 lb-ft. Once again with Launch Control, it'll blast to 60 mph in 3.5 seconds and top out at 185 mph. Amazingly, those power and performance specs are very similar to last year's Turbo. All Panamera E-Hybrid models have a 27 percent improvement in battery capacity and recalibrated drive modes.

The so-called standard Panamera and Panamera 4 also receive a new engine, the same 2.9-liter twin-turbo V6 (instead of last year's 3.0 turbo V6) found in the hybrid, only without electrification. Total output is rated at 325 hp.

Regardless of what's under the hood, all 2021 Panameras have a number of exterior styling enhancements, beginning with the previously optional SportDesign front fascia now being standard. A SportDesign package, available with carbon fiber, is optional.

Take note of the new light strip running across the entire rear end connecting the taillights, a restyled rear fascia with new diffuser fins, and new 20-inch and 21-inch wheel designs.

The GTS's front fascia now comes in Satin Black and there are trim-specific black 20-inch wheels, tinted taillights, black lettering designating the trim, and a standard Sport Exhaust System.

The new Turbo S also has its own front fascia design featuring larger air intakes and a unique lighting signature. Two new exterior metallic colors are available: Cherry Red and Truffle Brown.

As for the interior, a new multifunction steering wheel is found in base models while the Turbo S boasts a new GT Sport steering wheel wrapped in leather. Eight-way electronically adjustable seats are standard, with the Turbo S benefitting from 14-way adjustable seats and the GTS getting 18-way adaptive sport seats. The center console's 12.3-inch touchscreen features navigation and a WiFi hotspot. Turbo S owners will enjoy a 14-speaker Bose sound system and there's even a 21-speaker Burmester surround system available on all trims.

Also standard on all trims is the Porsche Active Suspension Management system that's received calibration updates. The Turbo S, however, comes with the Porsche Dynamic Chassis Control Sport-roll stabilization system, torque vectoring, and ceramic composite brakes. These are also optional on all lower trims. And, for the first time, Porsche is offering ultra-high performance summer tires on all trims. Standard safety includes Lane Keep Assist and Traffic Sign Recognition.

Customer orders for the 2021 Porsche Panamera lineup will begin early 2021 when pricing will also be announced. Deliveries will begin next spring.