diff --git a/selfdrive/car/hyundai/carcontroller.py b/selfdrive/car/hyundai/carcontroller.py
index 0e3a3f0afd..e121faa790 100644
--- a/selfdrive/car/hyundai/carcontroller.py
+++ b/selfdrive/car/hyundai/carcontroller.py
@@ -4,6 +4,7 @@ from openpilot.selfdrive.car import DT_CTRL, apply_driver_steer_torque_limits, c
 from openpilot.selfdrive.car.conversions import Conversions as CV
 from openpilot.selfdrive.car.helpers import clip
 from openpilot.selfdrive.car.hyundai import hyundaicanfd, hyundaican
+from openpilot.selfdrive.car.hyundai.carstate import CarState
 from openpilot.selfdrive.car.hyundai.hyundaicanfd import CanBus
 from openpilot.selfdrive.car.hyundai.values import HyundaiFlags, Buttons, CarControllerParams, CANFD_CAR, CAR
 from openpilot.selfdrive.car.interfaces import CarControllerBase
@@ -169,7 +170,7 @@ class CarController(CarControllerBase):
     self.frame += 1
     return new_actuators, can_sends
 
-  def create_button_messages(self, CC: car.CarControl, CS: car.CarState, use_clu11: bool):
+  def create_button_messages(self, CC: car.CarControl, CS: CarState, use_clu11: bool):
     can_sends = []
     if use_clu11:
       if CC.cruiseControl.cancel:
diff --git a/selfdrive/car/interfaces.py b/selfdrive/car/interfaces.py
index 4e434ec386..4707ade718 100644
--- a/selfdrive/car/interfaces.py
+++ b/selfdrive/car/interfaces.py
@@ -87,7 +87,7 @@ def get_torque_params():
 # generic car and radar interfaces
 
 class CarInterfaceBase(ABC):
-  def __init__(self, CP, CarController, CarState):
+  def __init__(self, CP: car.CarParams, CarController, CarState):
     self.CP = CP
 
     self.frame = 0
@@ -97,7 +97,7 @@ class CarInterfaceBase(ABC):
     self.silent_steer_warning = True
     self.v_ego_cluster_seen = False
 
-    self.CS = CarState(CP)
+    self.CS: CarStateBase = CarState(CP)
     self.cp = self.CS.get_can_parser(CP)
     self.cp_cam = self.CS.get_cam_can_parser(CP)
     self.cp_adas = self.CS.get_adas_can_parser(CP)
@@ -116,7 +116,7 @@ class CarInterfaceBase(ABC):
     return ACCEL_MIN, ACCEL_MAX
 
   @classmethod
-  def get_non_essential_params(cls, candidate: str):
+  def get_non_essential_params(cls, candidate: str) -> car.CarParams:
     """
     Parameters essential to controlling the car may be incomplete or wrong without FW versions or fingerprints.
     """
@@ -151,7 +151,7 @@ class CarInterfaceBase(ABC):
   @staticmethod
   @abstractmethod
   def _get_params(ret: car.CarParams, candidate, fingerprint: dict[int, dict[int, int]],
-                  car_fw: list[car.CarParams.CarFw], experimental_long: bool, docs: bool):
+                  car_fw: list[car.CarParams.CarFw], experimental_long: bool, docs: bool) -> car.CarParams:
     raise NotImplementedError
 
   @staticmethod
@@ -211,7 +211,7 @@ class CarInterfaceBase(ABC):
     return ret
 
   @staticmethod
-  def configure_torque_tune(candidate, tune, steering_angle_deadzone_deg=0.0, use_steering_angle=True):
+  def configure_torque_tune(candidate: str, tune: car.CarParams.LateralTuning, steering_angle_deadzone_deg: float = 0.0, use_steering_angle: bool = True):
     params = get_torque_params()[candidate]
 
     tune.init('torque')
@@ -342,10 +342,10 @@ class CarInterfaceBase(ABC):
 
 
 class RadarInterfaceBase(ABC):
-  def __init__(self, CP):
+  def __init__(self, CP: car.CarParams):
     self.CP = CP
     self.rcp = None
-    self.pts = {}
+    self.pts: dict[int, car.RadarData.RadarPoint] = {}
     self.delay = 0
     self.radar_ts = CP.radarTimeStep
     self.frame = 0
@@ -358,7 +358,7 @@ class RadarInterfaceBase(ABC):
 
 
 class CarStateBase(ABC):
-  def __init__(self, CP):
+  def __init__(self, CP: car.CarParams):
     self.CP = CP
     self.car_fingerprint = CP.carFingerprint
     self.out = car.CarState.new_message()
@@ -380,6 +380,10 @@ class CarStateBase(ABC):
     K = get_kalman_gain(DT_CTRL, np.array(A), np.array(C), np.array(Q), R)
     self.v_ego_kf = KF1D(x0=x0, A=A, C=C[0], K=K)
 
+  @abstractmethod
+  def update(self, *args) -> car.CarState:
+    pass
+
   def update_speed_kf(self, v_ego_raw):
     if abs(v_ego_raw - self.v_ego_kf.x[0][0]) > 2.0:  # Prevent large accelerations when car starts at non zero speed
       self.v_ego_kf.set_x([[v_ego_raw], [0.0]])
@@ -462,12 +466,12 @@ class CarStateBase(ABC):
 
 
 class CarControllerBase(ABC):
-  def __init__(self, dbc_name: str, CP):
+  def __init__(self, dbc_name: str, CP: car.CarParams):
     self.CP = CP
     self.frame = 0
 
   @abstractmethod
-  def update(self, CC: car.CarControl.Actuators, CS: car.CarState, now_nanos: int) -> tuple[car.CarControl.Actuators, list[CanData]]:
+  def update(self, CC: car.CarControl, CS: CarStateBase, now_nanos: int) -> tuple[car.CarControl.Actuators, list[CanData]]:
     pass
 
 
diff --git a/selfdrive/car/mock/carstate.py b/selfdrive/car/mock/carstate.py
index ece908b51c..41a298e24e 100644
--- a/selfdrive/car/mock/carstate.py
+++ b/selfdrive/car/mock/carstate.py
@@ -1,4 +1,7 @@
+from cereal import car
 from openpilot.selfdrive.car.interfaces import CarStateBase
 
+
 class CarState(CarStateBase):
-  pass
+  def update(self, *args) -> car.CarState:
+    pass
diff --git a/selfdrive/car/subaru/tests/test_subaru.py b/selfdrive/car/subaru/tests/test_subaru.py
index 33040442b6..f81c392679 100644
--- a/selfdrive/car/subaru/tests/test_subaru.py
+++ b/selfdrive/car/subaru/tests/test_subaru.py
@@ -1,10 +1,5 @@
-from cereal import car
 from openpilot.selfdrive.car.subaru.fingerprints import FW_VERSIONS
 
-Ecu = car.CarParams.Ecu
-
-ECU_NAME = {v: k for k, v in Ecu.schema.enumerants.items()}
-
 
 class TestSubaruFingerprint:
   def test_fw_version_format(self):
@@ -13,4 +8,3 @@ class TestSubaruFingerprint:
         fw_size = len(fws[0])
         for fw in fws:
           assert len(fw) == fw_size, f"{platform} {ecu}: {len(fw)} {fw_size}"
-