Have your buddy help you put them on the car. They should fit and be fine. You will really like the Koni's if they are adjustable (Front). I think rear adjustable is pretty much set it where you want and then put it in. I would not go full hard by any means. Maybe set the rears at 1/3 hard to 1/2 hard, no more.
The fronts take about 3 hours max and rears about 2 hours max. I could probably do both in 3 hours ez but I've done it a few times.
If the price is right, I think you will be happy with this combination, especially the shocks.
Mike Holbrook
Meridian, Idaho
1992 535im, 17", Euro M5 Throwing Stars 8's & 9's, FK-451 235/45s & 255/40s, M5 Sway Bars 25/20, Conforti chip, Lowes Ram Air, glass sunroof