I got to change the front ball joint on 1 side of the car, but will do both as i was kindly given the pair when i bought the car

Thing is these are the bolt on one, i have never fitted these before, i have always had full wishbones and replaced in one unit.

How easy is it to change just the ball joint part? how much should i pay to have it changed? Will it need Laser/wheel alliment after?

And one last question, can you get wishbone poly bushes for the estate tdci mondeo`s? as thinking maybe poly bush an old set of nackered wishbones and fit the new ball joint onto them.