If you're lowering/raising your car for the first time, you WILL need to get an alignment. Lowering your car will cause a Toe in, wearing the insides of your tires out. I just went through a set of tires on my rear in like a month 1/2 because I could not get my car aligned (the car sat to low). I was told that you should get your car aligned everytime you raise/lower. However, if you're only doing a fractional raise/lower of the car then I see nothing to worry about.