had one in the past, it's not much taller. use the 1.3 tensioner (1.8 one is also smaller i believe) if you can get hold of one. make sure the profile of the belt teeth is the same on the pulleys as i know the 1.8 had square teeth, so the 1.9 may have also.

as for the exhaust - it should be fine. the block isn't loads taller than a 1.6, it just makes more of a difference at the belt end