engine B4184S11 vs B4184S8
 

So my situation is following: my volvo S40 (1.8L) -05 has an engine fault and my mechanic says that it would be cheaper and better option to change the whole engine. Now the only problem is that I can't find the right engine anywhere, my engine is B4184S11, the closest thing I can find is the flexfuel version which is B4184S8. I know the flexfuel version can run with pure gasoline also, so it's no problem from that perspective, only thing I'm worried about is that is the flexfuel engine any different in size? So can it be just fitted straight in the place of my old engine?

If anyone has any experience/knowledge about these engines, any help would be appreciated.