Will VÅGSTRANDA Pocket spring mattress, medium firm/white, Queen fit in an Alfa Romeo 159 2010?

The 159 gives you plenty of height at the opening and less width than you would like. The mouth measures 36⅝″ wide by 50¾″ tall, so tall boxes go in easily, and the floor matches it at 36⅝″ across its narrowest point. Length runs 40⅛″ with the seats up and 69⅝″ folded, a gain of 29½″. Wide, rigid cartons are the ones that fight you here. The sill is 30⅜″ off the ground with a 9⅞″ drop to the floor, so lift over the lip and lower, rather than sliding.

VÅGSTRANDA ships as one box, and it is a heavy one: 65¾″ × 17¾″ × 17¼″ at 109 lb 6 oz. IKEA rolls and compresses the queen mattress, so instead of a floppy slab you get a short, dense block that two people can carry and one person will regret. The length is friendly; the weight is the problem, and the box gives you no handles. Most hatchbacks take it with the rear seats folded, and a wagon or SUV swallows it without drama. Load it last, on its side, so it slides straight out at home, and keep the wrapping sealed until the bedroom: once it expands, it never rolls back up.