When Porsche's new four-door Panamera goes on sale this fall, it will have two powertrains available: a 4.8-liter V8s with and without turbochargers. The only other powertrain Porsche has committed to is the hybrid system that will debut in the Cayenne next year. Two other options are likely to appear in the Panamera as well. A gasoline V6 is probable, most likely the new 3.0-liter supercharged V6 that is debuting in the Audi S4 and A6 this year.
The other option may well be a diesel from within the Volkswagen Group. The 3.0-liter TDI V6 is launching in the Cayenne this year and is the most likely candidate for the Panamera. Given the Panamera's performance capabilities, it could also get the 4.2-liter TDI V8 that's used in the European Audi Q7 and A8. The choice of diesel or hybrid Panameras would help Porsche meet upcoming CO2 emissions regulations in Europe and the USA.