Bought the pump for near 70, and had my friends dad change it for 100 bucks. I was going to pay him 150 for the difficulty but... he insisted i not pay him the rest.
As far as difficulty, Tools make the difference wether you have hard time or shit out of luck in hell. Either way, its harsh.
My opinion is to get someone who knows what they are doing to do it, even if you have to pay a little more, this way, something goes wrong, BLAME THEM!