the US spec monteros that had factory infinity amps in them had a compartment under the 2nd row seat right side of vehicle as you sit in it. not sure if pajeros had that same compartment, but it is a large compartment and you can see it if you look just above the tire through the fender well gap between the frame and body.

you have to life the carpet up and there is a large metal plate bolted down, kinda like the plate to access the fuel pump on the gas tank, but instead, it is further frontwards and under the right second row seat. I can pics of mine on my montero if you need them.