To get the full benefit of adjustable coil overs you'll want to get the car corner weighted, and you will (or may) want to do some testing to determine the final ride height settings (before corner weighting the car) and shock settings. Depending on the particular coil overs you select, you may be able to juggle spring rates and shock valving as a part of your suspension tuning program. You'll also probably want to do come critical alignment tuning; A skid pad, pyrometer, stopwatch, and G-meter, can all be useful in this regard.

If you're just dropping the car for looks, and are going with coil overs just so you can adjust the ride height, all you have to do is set the ride height where you want it and get the car aligned. Every time you change the ride height, you'll need another alignment.