i've made a map based on the mission in mta and tested few things, this is what i figured out. This might be not perfect comparison but you've got the idea, also i wasn't using lean forward acceleration because in this mission you're driving with cesar.

NVM, Flying already showed this way, didn't know that because i never read any speedrun forum, just saw reset not using this one and i thought noone knows it

Not worth it in a long term. First of all airport jump is inconsistent (low bike skill, parked helicopter, lamppost). Also with this driving route you can't skip pausebuffering, which loses you quite a bit amount of time.