Im pretty sure its a long time to do it and fit it so it appears OEM+... 6-8hours at a guess.
Using the washer bottle and mounting the pump in the engine bay is a faster job as you don't have to strip half the car apart.
To do a perfect install including fitting the spacer plates etc can take up to 10 hours. Using the washer bottle and mounting the pump in the engine bay is a faster job as you don't have to strip half the car apart.