[aerohead]

carmakers have known for many decades that changes in inclination can effect drag.
There is a risk that Volvo has already optimized the inclination angle on your car during its development.
A few studies were published and no two cars behaved the same.I don't have all that with me,sorry.
The Ford Probe-IV would drop its nose about 3-inches,then raise its tail a smidgeon,increasing the attack for the top of the car,without increasing its overall height (frontal area).
From a safety standpoint,it might be better to lower the nose than to raise the rear.Some cars were given active suspension so that the car would maintain a constant rake regardless of load.It was a safety issue.Progressive-rate springs were developed in part to mitigate these effects.
Renault's VESTA Plus concept car enjoyed a 0.004 drag reduction from a 0.75-degree nose drop.
Without a wind tunnel its a tough thing to figure out.