Yesterday I decided to give it a try. I started game, logged in regularly GFWL/Social Club and played with all settings off when possible or when not possible, the lowest option. Including texture quality.
I started ALT+P, went on duty, some point after that my game briefly alt-tabbed, blackscreened and then it resumed. After closing it down I found out that the generic ''a problem occurred with GTAIV.exe and it had to be closed'' window popped up, however my game kept running - and it ran very smoothly: no lags, no crashing, nothing. I played for like an hour and it functioned normally with no issues at all!
Problem now is I don't know what makes this ''fake crash'' happen...