Factory driver Preining won twice in Porsche's first season in the DTM last year with two-time Le Mans 24 Hours winner Timo Bernhard's operation, following up the Weissach marque's first series victory at the Norisring with a charging drive at a wet Red Bull Ring, while Porsche-contracted Olsen dominated from pole for SSR Performance at Spa.
Preining's move to join the incoming Manthey effort was predicted by Autosport last month and, with SSR switching to Lamborghini, announcing factory drivers Mirko Bortolotti and Franck Perera as part of its three-car roster on Thursday, Olsen has moved across to join him at Manthey following the conclusion of its works involvement with Porsche in the World Endurance Championship's now-defunct GTE Pro class.
Preining said: "The crew is highly professional and the chemistry is right. We are all very motivated.
"I'm looking forward to the season with confidence and can't wait for it to finally start."
Olsen added: "I've already worked with the team and I know how well things work at Manthey. This is topped off by the new generation Porsche 911 GT3 R.
"For me this is exactly the right starting point to race at the highest level in the DTM."
Bernhard, meanwhile, will run Asian Le Mans Series champion Ayhancan Guven and German Carrera Cup champion Laurin Henrich in its two cars.
Two-time French Carrera Cup champion Guven finished second in the ADAC GT Masters standings with Porsche outfit Joos Sportwagentechnik last year and also made a strong impression on his DTM debut at the Norisring with the Red Bull Ferrari team by qualifying third for his debut.
"Joining the DTM grid is a huge moment for my career and something I was dreaming for a long time," said the Turkish driver.
"We all know how tight and difficult the current DTM grid is so it will not be an easy season for anyone but, with experience from the team, we will try to put right steps together."
Henrich, a former Porsche junior, is now a Porsche contracted driver with the same status as Olsen.
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Manthey returns to the DTM for the first time since it ran Mercedes in 2002, an involvement capped by winning the last two rounds of the 2001 season with Patrick Huisman and Bernd Maylander at Hockenheim.
Team founder Olaf Manthey also has a long history in the DTM, having finished second in the inaugural championship in 1984 and repeated the feat in 1985.
Manthey Racing's tie-up with Australian outfit EMA Motorsport continues a burgeoning partnership that yielded second spot at the Bathurst 12 Hour earlier this month, with Preining part of its driver line-up.
The two organisations previously collaborated on an entry to the Spa 24 Hours last year as well as in a round of the Nordschleife-based Nurburgring Endurance Series.
Toksport WRT was also revealed as a Porsche entrant for 2023 when the series now run by the ADAC - following its sale by Gerhard Berger's ITR organisation - revealed its 13 participating teams on Wednesday and announced on Friday that 2020 ADAC GT Masters champion Christian Engelhart will be partnered by two-time DTM Trophy champion Tim Heinemann.
Engelhart made his DTM debut with SSR in place of Laurens Vanthoor at Hockenheim last year, taking a best finish of 14th.
Meanwhile, one-time Formula 1 race starter Jack Aitken will join the grid in a Ferrari 296 GT3 entered by Emil Frey Racing. Aitken will continue his relationship with the team - which began in GT World Challenge Europe in 2021 - into a third season, joining fellow debutant Thierry Vermeulen upon the Swiss team’s entry into the DTM.
Aitken had previously competed in both the GTWCE and the ADAC GT Masters for Emil Frey Racing, scoring a victory in the latter series last year, but is now expected to focus entirely on the DTM with the squad.
