These are CAR TYPE = Race, and not eligible for the Tuners of Japan Speedway event. The restrictions are CAR TYPE = Pre-Tuned and REGION = Asia and a maximum class of R3 (any PI less than 801). If you go create an online private race with these restrictions you can see the possible dealer choices that would be eligible (though would need to be tuned up to be competitive):
Mazda Mazdaspeed Familia
Mazda Mazdaspeed Roadster
Mazda RX-8 Mazdaspeed
Mazda Mazdaspeed 3 (2009)
Mazda Mazdaspeed 3 (2010)
Honda Mugen Civic Type-R 3D
Hundai Rhys Millen Racing Genesis Coupe
If you have one of the unicorns they can also be used: Mitsubishi HKS, Nissan Mine's R32, Nissan Mine's R34, Nissan Top Secret S15, Toyota Top Secret Supra.