Will MARKUS Office chair, Vissle dark gray, Medium 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 MARKUS chair travels as a single box of 38½″ × 24¼″ × 9½″, short enough to lie flat in most trunks without folding a seat. The catch is density: 49 lb 6 oz packed into that footprint, so the box is far heavier than its size suggests. There is no long dimension to fight, which makes this an easy load for a sedan or hatchback, and an SUV will not notice it. Treat it as a two-person lift anyway, slide it over the sill on its long edge instead of carrying it flat, and load it last so the weight sits near the opening when you unload.