Yeah, this is next level track.
So, I did a few changes. Mainly to make road go smoother, and less surprising. After all, the time needed and length is here challenging already.
I also added another pipe glass lookout section, bit longer, can be seen on view below. It goes out of, and back to that cave that had a small gap for view. I also extended a bit that higher pipe lookout. Fixed some terrain to road transitions.
Dropped snow pines, I didn't see many, and at such heights they wouldn't grow I think.
Restored more grass. It doesn't drop FPS for me and looks better.
Added stone/gray road up top. And made some variations in surfaces tab. Reworked checkpoints (even less).
Whole road is broader now, and has more grip. Pipes are more clear.
Ah and I did flatten terrain under water, and also on map edges. Took a while, but I think this can affect FPS.
Also for same reason, made water areas smaller to fit, and shore bigger. Made water deeper, in case anyone went into it.
Now after few times, I drove it in 14min 28sec.