Update: I have since left Braveheart, and now use vpcallouts. Not to be confused with VipCallouts. I have never crashed while responding to a call from vpcallouts. Hope this info helps, but remember that crashing comes mostly from cars that are too high poly, or from pursuits.
Well I'm able to play for up to 3 hours. These are simply my preferences, yours may differ from mine.
I only modify 1 police vehicle, and I make sure the download is less than 6 mb. (CJ24's NYPD CVPI from 2013 I think)
I never respond to a call that turns into a pursuit, nor do I take part in pursuits as they always crash.
I have installed Braveheart's Policing Script, and therefore I press F7 to turn off LCPDFR callouts because they're mostly buggy anyway.
If a pursuit starts during a traffic stop, immediately shoot the driver (works for me)