That explains the weight difference (4300kg vs. normal weight 4392kg). 92kg=115 litres of fuel, so aux. tank was probably empty.
It cannot be mounted and flown without rack. Empty or not, Timras.
The set up also claims GM-1 installation. Where was GM-1 installed??
The 85 liter tank is the ONLY tank that was authorized for GM-1 use. This tank was specially insulated to maintain the LNOX for as long as possible. Even then, Luftwaffe regulations dictated that the aircraft must be flown within a certain time period of being serviced with LNOX.
The system weighed 104 KG's installed and gave 21.7 minutes of use.
All the best,
Crumpp