he best car I found for S1 is a Ferrari F40 the second best is the Lamborghini Diablo, both with 4WD.
It is ok to hit the walls, side on slightly or with the rear corner of the car, do you have the driving line turned on? I have it for breaking zones only, you don't want to go in at huge speed, it is much better to brake then hit the wall.
I am from the grip side, what you need is to get into drifting for Horizon games, you don't need to be a drift master, but you need to learn to drift progressively, so the rear of the car steps out slightly.
The best way I can advise to learn how to drift better is
with this car and tune on the drift challenge just outside the desert site
or anywhere else, have a look at some of the other comments from members in the comments after that post.
It is a monster, but it will help you get better at holding a car around and through corners, once you can get the 'feel' then you can do it with every car on any track and surface, you don't need to become a drift-king, but it really does help, the track surface on the HotWheels track is weird and even the top players/drivers are having to adjust from what I have heard and seen.