Wasn't FlatOut 2 mostly a track racer?
I had an immense amount of fun with 1, but yeah, the unforgiving nature sucked. Especially combined with wonky physics. The ice level killed me, as there was this one time that I had gone off the level right before a checkpoint. In that game it was usually quicker to have it replace you then circle around. Thing was, it replaced me with two wheels on a big pile of ice and two wheels in midair. Any kind of acceleration either forward or reverse sent me off course, as I only had power from one side of my car. This would make me spin out and miss the checkpoint again.
The game was balls-to-the-wall fun at almost all times, but that's because you drove by the seat of your pants. Half the time you'd get air at a weird angle and fly into a tree, or past a checkpoint. You'd then see yourself go from first to a distant 8th. It would have been nice if the computer messed up as often as you did. Because that was the charm of the game - how fast and out of control you were at almost all times.
I played with an Xbox controller hooked up to my PC, and to get very analog acceleration I had the right stick for it. Push up to accelerate. Push back to reverse. Sounds weird, but I found it easier than the shoulder buttons for that game.