Comparing sector times we can know if it´s a poor chassis or a good one configured like it is, for example is Spa S2 it looked like a good chassis, but we don´t know if its configuration was the ideal to shine in that sector, or if they still have some more margin they´re not using because of the lack of power
a very good chassis can run skinny rear wings like redbull and mercedes and still get good efficient downforce through the floor section and that why redbull and mercedes set the benchmarks in chassis peformance. we both saw how thiny the rear wing are of both, inefficient chassis like william or mclaren try to get the downforce through a large rear wing, this is ineffficent downforce causes loss of straight line speed, and especailly in power circuit u have run skinny wing to get good straight line speed. mclaren ran a large rear wing so did william and both struggle in the straights, william could not overtake alonso and william got overtake by others easily , wrong setup.
Anyway what is your expectation for monza, i pretyy sure you will say no points for mclaren.