Final 991-series Porsche 911 sells for $860,000

The last Porsche 911 Speedster ever has been auctioned off in the US for $550,000 ($A860,000), with all proceeds going to victims of the coronavirus outbreak.

Following the online RM Sotheby's auction, Porsche Cars North America announced that it would almost double the amount donated to the Untied Way Worldwide charity by adding a further $500,000 ($A785,000) to the sum raised.

The last 911 Speedster ends a run of 1948 cars and finally brings an end to production of the 991-series Porsche 911.

Painted in GT Silver Metallic paint and complete with the Heritage package, the special drop-top Porsche is said to have been customised in the spirit of famous Porsches from the '50s and '60s.

The Heritage pack, as well as the silver paint, adds black brake callipers with silver Porsche logos, silver coloured alloy wheels, gold Speedster badging and two-tone black and cognac leather trim.

Under its rear boot lid lives the same 4.0-litre naturally-aspirated flat six-cylinder that's used in the 911 GT3 RS.

In the Speedster, the 4.0-litre boxer pumps out a healthy 374kW and 470Nm of torque, and is combined with a smooth-shifting six-speed manual transmission.

Porsche says the 911 Speedster, which also features a unique soundtrack courtesy of individual throttle bodies and a bespoke exhaust, will hit 100km/h in just 3.8sec on its way to a top speed of 309km/h.

In addition to the special Speedster, the highest bidder will receive a Porsche Design Heritage Design Chronograph watch that uses the same cognac leather for its strap and has the chassis number of the final 991 engraved on it.

The car also comes with a letter of authenticity signed by Frank-Steffen Walliser, the 911's chief engineer, and Andreas Preuninger – the man in charge of the Porsche GT division.

If that’s not enough to tempt a sizeable bid, Porsche USA will throw in an exclusive behind-the-scenes tour of Porsche’s R&D centre in Weissach, Germany, plus guaranteed track time with both the 911 and GT models.

The future owner will also receive an original sketch of a proposal for the Speedster from Porsche’s design team and a book that details the 911 Speedster’s assembly.

In Australia, the new Porsche 911 Speedster is priced from $604,800 (plus on-road costs), making it one of the car-maker’s most expensive limited-edition models to date.