Frankly, at times you run, I don't think you'll notice the difference
between 160 and 170. At least I can't. What is noticable is the balance
between front and rear. Set it so the car is balanced in T1 and through the
tunnel. I would try softer bars though, something like 130/130. Another
thing is, do you run with steering hack? AFAIR it's on by default in GPL.
It causes the steering ratio to decrease at slow speeds (for example, if
you have 14:1 in your setup, in slow corner it may progressively go to 7:1
or something like that). Needless to say it messes up your car control. At
Monaco it is particularly noticeable as there're so many slow corners. The
caveat is if you're used to run 14:1 or slower you will have some hard time
adjusting to 10:1, which is about what you need to make hairpins.
Anyway, whatever you do with setup, you need to be super-smooth at Monaco.
Then all those slow corners suddenly will become not so slow.
Alex.