Possible optimizations:

1. Get crew to consistently spot the relevant staging area vehicles instead of that stupid M60 driving left to right. Numbnuts just magically look at things that aren't visible via the sights I am pointing at them I guess. It's definitely possible, I was able to spot them once from as far as the right hand turn on top of the crest the moment they come into sight. Just need to find the right keys to jingle in front the the commander's eyes so he doesn't get distracted by irrelevant units (this is why I bother destroying the M113 in the first place, aside from not wanting to getting randomly run-killed by it destroying vital components - not killing it can lead to the crew getting hyperfocussed on it and ignoring the tanks in front of them). Possibly slowing down a bit to make it dip behind the second crest before cresting the first one yourself might do the trick.

2. Figure out a way to get the second tank into the Mission End trigger zone without having to switch back and forth. Theoretically something like echelon left and driving the normal route would work, if only the AI was less sluggish. Column and driving a hard left at the start might also work, but cost time for the setup. Experimentation needed.

3. Minutiae of the movement and shotboosting - exact path (possibly influenced by 1) and 2)), but also how exactly to get the most out of the shotboost. Which exact direction to shoot, when to shoot, and when to restock. In this run I seem to gain 4-5 km/h shooting more or less straight backwards. How does up/down angle affect this? Do ammo types matter? The overall effectiveness of this can not be understated. Before doing it, I only managed low 4s with the late staging spot. My only sub 4 run previously was the one where I got the early crest spot. The shotboosting can definitely shave off many seconds.