Please have the following parts readily available to replace with E0416 Long Chassis (+5).

P/N Description
E0416 Long Chassis (+5)
E0254 Center Drive Shaft (110)
E0188 Tension Rod
E0803 Fuel Tank Bush
B0734 SiG3X16 B/H Screw

As For information on how to assemble the rear body mount, see page 11 of the Manual for MBX-6 ECO.
Rear body mount is attached to E0188 Tension Rod.
Please make a hole in the body in accordance with rear body mount.