all brands can be done like this

selfdrive/car/interfaces.py

@@ -4,7 +4,7 @@ import numpy as np
 import tomllib
 from abc import abstractmethod, ABC
 from enum import StrEnum
-from typing import Any, Dict, Optional, Tuple, List, Callable, NamedTuple
+from typing import Any, Dict, Optional, Tuple, List, Callable, NamedTuple, cast
 
 from cereal import car
 from openpilot.common.basedir import BASEDIR
@@ -12,7 +12,7 @@ from openpilot.common.conversions import Conversions as CV
 from openpilot.common.simple_kalman import KF1D, get_kalman_gain
 from openpilot.common.numpy_fast import clip
 from openpilot.common.realtime import DT_CTRL
-from openpilot.selfdrive.car import apply_hysteresis, gen_empty_fingerprint, scale_rot_inertia, scale_tire_stiffness, STD_CARGO_KG
+from openpilot.selfdrive.car import PlatformConfig, apply_hysteresis, gen_empty_fingerprint, scale_rot_inertia, scale_tire_stiffness, STD_CARGO_KG
 from openpilot.selfdrive.controls.lib.drive_helpers import V_CRUISE_MAX, get_friction
 from openpilot.selfdrive.controls.lib.events import Events
 from openpilot.selfdrive.controls.lib.vehicle_model import VehicleModel
@@ -111,6 +111,14 @@ class CarInterfaceBase(ABC):
     ret = CarInterfaceBase.get_std_params(candidate)
     ret = cls._get_params(ret, candidate, fingerprint, car_fw, experimental_long, docs)
 
+    if hasattr(candidate, "config"):
+      platform_config = cast(PlatformConfig, candidate.config)
+      if platform_config.specs is not None:
+        ret.mass = platform_config.specs.mass
+        ret.wheelbase = platform_config.specs.wheelbase
+        ret.steerRatio = platform_config.specs.steerRatio
+        ret.centerToFront = ret.wheelbase * 0.5
+
     # Vehicle mass is published curb weight plus assumed payload such as a human driver; notCars have no assumed payload
     if not ret.notCar:
       ret.mass = ret.mass + STD_CARGO_KG

selfdrive/car/subaru/interface.py

@@ -40,12 +40,6 @@ class CarInterface(CarInterfaceBase):
     else:
       CarInterfaceBase.configure_torque_tune(candidate, ret.lateralTuning)
 
-    platform_config = CAR(candidate).config
-    ret.mass = platform_config.specs.mass
-    ret.wheelbase = platform_config.specs.wheelbase
-    ret.steerRatio = platform_config.specs.steerRatio
-    ret.centerToFront = ret.wheelbase * 0.5
-
     if candidate in (CAR.ASCENT, CAR.ASCENT_2023):
       ret.steerActuatorDelay = 0.3   # end-to-end angle controller
       ret.lateralTuning.init('pid')