Room 3-SP+ (titled Room 2-SP+ in the British English version) is the Special Level in the Plus Mode version of Magnet Mania in Mario vs. Donkey Kong: Minis March Again!. It is unlocked once all lettered Mini Mario Cards are collected on this floor.
The course features four mini toys.
All minis start around the center of the course, two on a long Magnet strip and another two on a short platform above them. The Goal Door is on a platform in the top left area of the stage. The minis have to be guided with Pink Blocks to one of the bottom Split Pipes, warping them to the top of the stage where the player should further place Pink Blocks to help the minis reach the door.
Mini Mario Card
The Mini Mario Card is on a platform at the top, on the same level as the Goal Door. To obtain it, the minis have to use a Split Pipe to reach the top and then be guided to the card with Pink Blocks.
The M-Token is in a Magnet alcove in the bottom left. To collect it, the minis have to either walk around the Magnet after coming out of the bottom cyan Split Pipe, or simply be guided with Pink Blocks from the platforms on the right to the token.