Three straight championships (2014–2016)

For the newly formed IMSA SportsCar championship in 2014, AXR ran only the No. 5 of Barbosa and Fittipaldi for the full season, reducing the No. 9 crewed by the Frissele brothers and Jon Fogarty to only the North American Endurance Cup. AXR took three wins, including the team's second Rolex 24, en route to both the inaugural title and North American Endurance Cup for the No. 5.^[2] For 2015, AXR assumed operations of the No. 31 Whelen Racing team, hiring GTD champion Dane Cameron to pair with Eric Curran.^[3] The No. 5 took its second IMSA title as well as the NAEC on the back of two wins including the 12 Hours of Sebring and Petit Le Mans, while the No. 31 team won at Detroit and Road America to finish 3rd in points.

The No. 5 and No. 31 remained unchanged in 2016. With their worst finish being 6th and two wins at Canadian Tire Motorsports Park and Road America, the No. 31 Corvette team won the drivers title, with the No. 5 team taking home another North American Endurance Cup.^[4]

Cadillac partnership (2017–present)

From 2017, both Mustang Sampling Racing and Whelen Engineering Racing fielded Dallara-based Cadillac DPi-V.R machines.^[5] The Rolex 24 At Daytona saw the Mustang Sampling Cadillac knocked from the lead on the penultimate lap by Wayne Taylor Racing, another Cadillac team. Following the Daytona outing near-miss, the team continued to learn the new Cadillac Prototype as the No. 10 team had a strong start to the season. Mustang Sampling Racing returned to the winner circle at Watkins Glen and began to gain momentum. Even with both cars taking wins, compared to the last three seasons, had a relatively disappointing year, the Nos. 5 and 31 only winning one race each, and watched the rival Wayne Taylor Cadillac win the first five races on their way to the WeatherTech Championship, however the No. 5 once again took the NAEC, their fourth in a row.

2018 brought changes to the team. Christian Fittipaldi moved to an endurance driver/manager role in the team, while Dane Cameron left to join Team Penske's new Acura program. Their spots on the team were filled by Filipe Albuquerque and ex-F1 driver Felipe Nasr, respectively.^[1] The team started the 2018 season with a 1-2 finish at the Rolex 24, setting an all-time distance record.^[6] The Mustang Sampling car then won at Long Beach, with the Whelen Engineering Racing squad taking a victory at Detroit, and eventually capturing both the WSCC and NAEC for 2018.

For 2019, the Pipo Derani joins the team in the No. 31 from Extreme Speed Motorsports, filling a void left by Eric Curran's move to endurance driver role. Additionally, Christian Fittipaldi will leave the driver's seat as he finishes his transition to a management role following the 2019 Rolex 24 at Daytona.^[7]

In 2021, 7-time NASCAR Cup Series champion Jimmie Johnson joined the team in a brand new entry, the No. 48 Ally Cadillac Racing Cadillac DPi-V.R. Simon Pagenaud, Kamui Kobayashi and Mike Rockenfeller joined Johnson in the car, which finished 2nd at the Rolex 24 at Daytona. Johnson's former Hendrick teammate and defending NASCAR champion Chase Elliott joined the #31 Whelen Engineering Cadillac DPi-V.R team during the Rolex 24 at Daytona as well.