It is the oil control valve for the VVT. The MDS is the other four solenoids that you removed already. No you wouldn't need it. You'll have to lock the cam phaser(upper cam gear, it's three main pieces) to prevent timing issues. Stanke Motorsports makes a billet plug for the VVT valve. Or just reuse the actual valve as a plug. Make sure you use the NON-MDS plugs for their respective cavaties.
