It would be very interesting to do a comparison run of that and the 120i to see if the diesel was more economical. It is on my "list" of things I will probably never get around to doing!
Actually it is the petrol version of the tank engine in the car (they were initially petrol but were converted to diesel when it was realised that petrol and live munitions was not a particularly good combination to have around).
No The 240 Wagon has a petrol engine. It is only more recently that Volvos have been available with a diesel engine I think maybe the 740 was the maybe the first that could have been had with a diesel.