https://go.twitch.tv/videos/53571818
I use the first line on the vertical axis to aim, aligned such that the right side covers the Stallion's nose and the left side is just under it. To trigger his death just grind the wall past the lamppost as you drive back.
This only only useful if you already have a sniper rifle at this point in the run, so it's not really usable for Any%, but might still be useful for some All Missions or 100% routes
A different snipe from the package location
I align the first vertical line on the right horizontal axis with the wall as shown in this image
Good for 100%
Or you can be really fast and try to pick up sniper during Sayonara? Of course if its fake time you might not be able to pick up uzi rampage at :10 but if time is real and u've got some time to spare I think its good to go for it edit: im dumb, u loose ammo on us dupe