Will VÅGSTRANDA Pocket spring mattress, medium firm/white, Twin 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.

The VÅGSTRANDA Twin arrives roll-packed as a single dense block, 43¾″ × 18¼″ × 17½″, weighing 69 lb 4 oz. The shape is friendly, the weight is not: it is a compressed pocket spring mattress, so all of that mass sits in a stubby bundle with no handles and a wrap that likes to slip. Because its longest edge is 43¾″, most hatchbacks swallow it with a seat folded, and many boots take it outright. Carry it with two people, load it on its long side, and leave the wrapping sealed until it is in the bedroom: once it unrolls, it never goes back.