speed sensor

I'm about to buy this Motor controller from pswpower But for the life of me, I cannot understand what this is supposed to mean: "Note:This is sensor controller, so controller has three big cable and five sensor wires and one speed sensor wire. you motor must have 8pcs wires or 9pcs wires, If...

I had a rear wheel rim replaced on my Bosch system ebike. The technician forgot to put the magnet back on the wheel. It will be several days before I can get the magnet. Will it cause any problems (other than unrecorded mileage) if I ride without the magnet? Details that I assume are irrelevant...