MILAN, June 18 (Reuters) - Maserati on Thursday presented revamped versions of its GranTurismo, GranCabrio and Grecale models, ahead of a key capital markets day in December aimed at setting a new course for the struggling Stellantis STLAM.MI luxury brand.

Outlining Stellantis' business plan last month, CEO Antonio Filosa said the automaker planned "to strengthen Maserati's future as a pure luxury brand", including with two new large-sized vehicles.

Future models will also include a brand new version of the Grecale SUV in 2027.

Besides Grecale, available in petrol, hybrid and fully electric, Maserati's current range features the GranTurismo coupe and its convertible version GranCabrio, offered both in petrol and fully electric versions. It also includes the low-volume MCPura sports car and its limited-edition derivatives.

New features for the revamped models include extended EV ranges and an upgraded 590 horsepower six-cylinder engine for GranTurismo and GranCabrio. A six-cylinder engine will now be available also on all the petrol versions of Grecale.

Maserati prices start from around €80,000 ($92,700) in Europe and around $80,000 in the United States.

On Wednesday, Filosa said the French-Italian group was in talks over Maserati's long-term plans with "two important partners, which can bring us technology, development and excellent ideas", adding it was choosing between the two.

Asked about potential partnerships during an online presentation of the revamped lineup, Maserati Chief Santo Ficili said, "We clearly seek, want, and must find excellence on the market in electronic architecture, in the supply of specific parts.... we're moving in that direction."

However, Ficili ruled out any partnership with Jaguar Land Rover and Tata Motors TAMO.NS, which last month signed cooperation agreements with Stellantis for the U.S. market and for India respectively.

Filosa on Wednesday also ruled out any possible Maserati sale despite its persisting struggles, including recent speculation of interest from China's BYD 002594.SZ.

"Maserati is not for sale, for sure," he said.

The marque shipped fewer than 8,000 cars last year, posting an adjusted operating loss of €198 million.
($1 = 0.8627 euros)