It might be a easy job if they are the right fit, I changed the rear shock for one of a R6 so I have adjustable dog bones to fit the R6 not sure they will fit to the Fazer correctly, should do but will have to see.
I did a part resto on my Xj 900 started it in the front yard but it was freezing, the wife felt sorry for me and let me drag it through the house into the conservatory, it took a bit of wiggling to get it back out when it was back together.?