According to
www.TamiyaUSA.com...
The MAN TGX 6x4 XLX & 4x2 XLX both use the standard 56506 stock bullbar.
BUT, you want sturdy, get the aftermarket ones, as their uprights are aluminum, where Tamiya makes their uprights from styrene, and only the crossbars are metal.
Jut google for the key words " animal guard 1/14 " and you'll find the Tamiya ones, and the aluminum aftermarket ones.
WhiteWolf