Iam a snail with nitro chemist set and a pint of coffee 1hr 00mins 33seconds was a boost managed run with 2 mistakes. Breeminator is a master 56:16 is impressive question is was there any cuts involved? the checkpoints placement seemed quite miserley for cuts to me. I quite like how absorbing the long race is.
There aren't any hugely significant cuts that I spotted, but there are quite a lot of little refinements you can make to exactly how you take some of the corners. There was only one cut I spotted that was more than a small refinement, but even that one isn't all that major, there's a little U-shaped bit of road at one point that you can eliminate by just going straight on instead of turning left down it, going close to the checkpoint, as there isn't another checkpoint within the U-shaped bit.
I think boost management is very important for it. Don't boost through the gear shifts, or you'll waste a huge amount of boost. If using automatic, you have to get used to stopping boosting just before you know the game will shift.
As always, learning the course will make you much better at it. I've done it 4 times now, on two accounts, doing it with the loan car then the owned car with parts. I suspect sub 58 is impossible for a solo run with the loan car.
Also, I know I reached the 10% point at 5:38, and 10x that is 56:20, so the first 10% seems to be a good indicator of the time you'll do. You probably need to be around 5:48 or faster to get under 58 at the finish.
Later edit... Okay, what I had labelled as "10%" in my mind was actually the start of the straightish bit where it later changes from 9% to 10%, so my times above were too fast. I just got under 56 minutes while arriving at the point where it changes from 9% to 10% at 5:47. I had some pretty bad luck with traffic later on, but if we assume that will usually happen to everyone, then it seems you probably only need to be around 6:00 at 10% to be in the right ballpark for getting under 58 minutes.
Also the bit I mentioned where you can miss out a U-shaped bit of road is at 79%.
There's a good video here of a low 54 minute run. A lot of what he does is very close to what I do, he just does it better, though I might have to give it a try with ESP off rather than sport, as he's doing a bit more deliberate sliding of the car, and I'd expect it to scrub too much speed if I did that with ESP sport.
If you look at 42:15 video time, around 42:05 into his run, that's the U-shaped bit you can cut out that I've mentioned, though it also shows another thing, which is that it's probably better to have rewind turned on, and use that instead of resetting when something goes wrong, as I've found it can reset you stationary a long way back, losing a huge amount of time. If you look at the comments, there's also a couple more places where he uses rewind to create a shortcut, though you don't need to use rewind for the 42:15 one, you can comfortably trigger the checkpoint without hitting anything.