Installing coilovers is a pretty long and painful job. I always started with measuring the standard height of the car and taking notes. It takes a little time to find the perfect height to your taste. It is not any longer than installing springs, should not be. Adjustments and fine-tuning the suspension is long. It gets more complicated if you have rebound adjustable c/os. 3,5 hours is pretty acceptable
ya my shipd took us almost 6 hours the first time when we did my car, luckily cause i worked at the shop at the time i barely paid anything but the second car we did alittle over 2 hours