I have always reversed into my garage, which is uphill at a reasonable pitch. The key is to start the manoeveur on a flat area, and keep a steady speed, I reverse back and turn to the left, one sweeping arc, up and into the garage, once there, the final jinks into a straight line, close to the wall, are essentially on the flat. By keeping the steady speed, I believe the clutch is fully off so the car is not riding it up the hill (which would be the problem). So far so good, not had any issues with any of the cars, ferraris, maseratis, Astons nor lambos, but I'm crossing my fingers.
Driving forwards into the garage for me is harder because the side the Ferrari lives has a low wall outside the garage that sweeps away, and to swing out would risk not seeing it, as my garage, while big in the UK, is slim compared to US type, and having a second car gives little wiggle room making you struggle to get much turning done until you are about out of the space, dancing dangerously close to the wall. Tried it in a 575 once and saved the nose by about 5mm! Never again.