Big difference between joystick and wheel. I started with a gamepad at the beginning but eventually got a wheel even though it was my only racing game.
Never regretted it, it gives you more consistency in your laps, more emersive feeling in the sim, and of course faster speed
Logitech wheels seem recomended here, MOMO Racing or Driving Force Pro.
Whatever you get, make sure it has force feedback like the 2 above.