Just a few notes. 1.5m would be too much for me at the bottom. Dig the house in a bit, 0.5 at the top, then 1.0 remains at the bottom, which is acceptable. I would also only place one parking spot next to the house, not one on the left and right. I would build the 2nd spot as a parking bay parallel to the street. We are also on a sloping street, but less so than you. Up at the house, we have a driveway and garage, not very steep, nicely easy to drive on, 3 m wide. Down below we have the mentioned parking bay with steps to the house and a fieldstone wall as support. Next to our houses on the left and right, the neighbors were only gently cut into the slope and everything was covered with grass and plants so that we keep the natural terrain as intact as possible and hardly have problems with water and such, the plants absorb it all. Karsten