I didn't need to remove the engine or anything else major to get the old out and the new in. It took a little maneuvering and bracket bending, but it was pretty much a pull-out and drop-in job. The manufacturer had used some form of adhesive on the tank and brackets (and I tested muscles I haven't used in a while, while contorted in a small space). I did have to eventually resort to an air-chisel to break the bonds of the old mounting brackets but after that the whole replacement took about 2-3 hours.