IMSA has confirmed the eligibility of cars competing in the Continental Tire SportsCar Challenge for the next three years, as part of the sanctioning body’s re-structuring of the series that will see the gradual introduction of new global platforms.

The majority of cars currently on the grid in both the GS and ST classes will be eligible next year, although a handful of models, which have taken part in some races this year, are set to be discounted by years’ end.

It includes the Porsche 997 and Ford Mustang Boss 302R in GS, as well as the ST-class Mercedes C300, all three of which were entered in this year’s season-opening round at Daytona, but with the exception of the Porsche, have not taken part in any races since.

As expected, the Porsche Cayman GT4 Clubsport, Ford Shelby GT350R-C, Aston Martin Vantage GT4 and Nissan 370Z will be grandfathered into the new-look GS class, which will adopt GT4 regulations next year.

Per IMSA’s revised Continental Tire Challenge Specific Car Regulations, the cars will be eligible through the end of 2017, with SRO-homologated GT4 cars from mainstream automakers set to become the exclusive platform in the class beginning in 2018.

The majority of current ST class cars, meanwhile, are expected to be eligible through the end of 2018, although a number of cars currently have unlisted eligibilities in the regulations.

While the ST class will remain unchanged through at least 2018, IMSA plans to introduce the TCR platform as an additional category in 2018, which could eventually replace ST.

Only 2016 registered cars are detailed in the list below. Additional cars, including SRO-homologated GT4 machinery, will be eligible beginning next year.

Cars Eligible Through Dec. 31, 2016:

GS:

BMW M3 E92

Chevrolet Camaro (Riley-Built)

Ford Mustang Boss 302R GT

Porsche 997 Carrera GTS

ST:

BMW 128i

Hyundai Genesis

MazdaSpeed3

Mercedes C300

Cars Eligible Through Dec. 31, 2017:

GS:

Aston Martin Vantage GT4

Ford Shelby GT350R-C

Nissan 370Z

Porsche Cayman GT4 Clubsport

Cars Eligible Through Dec. 31, 2018:

ST:

BMW 328i (E90)

Porsche Boxster 2.9L

Porsche Cayman 2.9L

Unlisted Eligibility:

ST:

Audi S3

BMW 328i (F30)

BMW 228i (F22)

Honda Civic Si (2012-2013)

Mazda MX-5 Miata

MINI Cooper JCW 2015

Nissan Altima V6