um ok
Driver Mission Spoiler
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3 things I do which have resulted in 100% success in 6 goes.
1.enter the mission with 2 stars.You are going to get them anyways.Get them inside the club and enter the "pink"..This results in Hilary's car being rammed on either side at the start causing him damage.
2.Hold look right(iirc) and shoot at the start.You can blow out a rear tire on his car or at least cause further damage.
3.You got it Pontiac.Park a fast car down aways from the start so it isn't removed by the cutscene.I like the first right.Actually get out and change cars.Hotring racer is king but any fast car will do.Hotring is just that much better.You will catch up quick.
Do all 3 and that should be enough to win easily.Know the course of course

2 other little helpers-
1-undoubtedly you may have noticed that near the Ocean Beach gunshop when you turn right,whoever is in front will often be rammed on either side by police.If you are still behind you can lift off the gas a touch and let Hilary get rammed.
2-if it is still close,you can cut the last corner by the police bribe
I have heard of people just waiting for him to come round and blow him up with rocket launcher but it never seems to work for me so I think it is an urban legend.
You can also try the police "pit" move and spin him out with the Sentinel.This is advanced driving though and not real easy.
But..when I beat him..why would I hire him?..always struck me as odd.