You should look under the car to see if the suspension is at its end and hanging almost against the silent blocks , then its a matter of stronger suspension.
If suspension is neatly in the middle , then recalculate the tire pressure with my spreadsheet for that you have to weight at best, but in lack of that , give the GAWR's front and behind and the specifications of the tires like maximum load and needed pressure for that read from the sidewall . also give the speedcode if you can find it( mostly N for 140km/87m/h ) .
Then I will give a picture of my filled in spreadsheet in my answer.