So...my 1988 740 Turbo Station Wagon is my workhorse car. The owner's manual has gone missing (that'll teach me to loan the car out) and I'm trying to haul some landscaping concrete blocks, 42 pounds (19 kg) each from Home Depot to my house. Would like to carry about 20-30 of them, so that would be up to 1260 pounds (573 kg) in the car.

Can I do that safely without harming my suspension, the car, or being too bad on the handling?

Thanks in advance!