For the 2013 Porsche Panamera, a new GTS model fills the gap between 4S and Turbo, while a Platinum version of the base V6 car also debuts.

The 2013 Porsche Panamera luxury sport sedan carries an ever-expanding portfolio of performance credentials. The Panamera lineup now includes rear-wheel-drive, all-wheel-drive, naturally aspirated and turbocharged models. There's even a gasoline-electric Panamera S Hybrid.

For 2013, Porsche fills the almost-imperceptible gap between the 4S and Turbo models with the new Panamera GTS that has attributes of its bookend brethren in one specially configured sedan. And this year also brings a fancier version of the entry-level V6 car, dubbed Platinum. These latest additions bring the impressive Panamera lineup to a total of 10 cars from which to choose. Among them, the list prices are separated by a cavernous $100,000, while engine output ranges from a respectable 300 horsepower to an awe-inspiring 550 hp.All models are well equipped for their price points, and Porsche has now made Bluetooth connectivity standard across the entire model line. As is the case with this luxury sport sedan segment -- and with Porsche in particular -- options can accumulate quickly and inflate the bottom line. Those options include luxurious items such as heated and ventilated articulating rear seats, video screens, dynamic enhancements like active suspension and carbon-ceramic brake discs, and the latest technology such as blind-spot monitoring and adaptive cruise control.

The 2013 Porsche Panamera is a four-door four-passenger sedan with a hatchback-style trunk. There are 10 trim levels: Base, Platinum, Base 4, Platinum 4, S Hybrid, S, 4S, GTS, Turbo and Turbo S.

The base rear-wheel-drive Panamera is powered by a V6 and includes 18-inch wheels, automatic xenon headlights, LED daytime running lights, rear parking sensors, a sunroof, a power rear hatch and auto-dimming mirrors.

Standard features within the cabin include dual-zone automatic climate control, a tilt-and-telescoping steering column, eight-way power front seats, driver memory functions, a chilled glovebox, partial leather upholstery and a 60/40-split rear seatback. Also standard are a navigation system and an 11-speaker sound system with Bluetooth, a USB/iPod interface and an auxiliary audio jack. The Panamera 4 differs only in that it has all-wheel drive. The Panamera S Hybrid is also very similarly equipped.

The Platinum and Platinum 4 trims are similar to their base brethren but dress things up and increase the luxury factor by adding 19-inch Turbo-style wheels, bi-xenon headlights, special exterior accents, upgraded leather upholstery, 14-way power seats, heated front and rear seats, front and rear park assist, a navigation system, a sport steering wheel (with paddle shifters) and unique door sill trim plates.

The V8-powered Panamera S and all-wheel-drive 4S include all of the features found in the non-hybrid base V6 models, plus an adaptive suspension, heated front seats, adaptive headlights and additional interior lighting.