In my case i have broken only a heater core but not Aircondition
It was necessary to put down only the part where the heater core is located, the left side only (driver side). The second picture is not mine but you can see.... that the right side where the air condition is located has six screws i think it's possible to put it down without to remove the fender but this is a very very difficult , probably you get a problem with two screws on the right side of the Ventilatorengine but if your fingers are not to big
perhaps you can fill it and blind 
work....in my opinion if you can put it down it's much more difficult to put it again inside 
but if you have a little bit time ... It is a big fun
