I looked into this some time ago also, I have the 80ltr combi and when in the back of my Patrol on the draws it can only go on the right hand side and the fridge slide only brings it out so far so ya have to have the compressor towards thefront of the vehicle, then when you open the fridge you have to climb over the spare on the back door to access the fridge, so I asked around and couldnt get any answers even emailed engel and they didnt answer, but when you take the lid of you can see that it is reinforced where the hinges are, and also the locks and they dont match up to do a swap so I dont think it can be done. To solve my problem I went and bought a 40 ltr for the car and keep the 80 for camping.