That price seems fair...I payed about $200 for the installation

Definetely get an alignment about a week after, just to allow the springs to settle in.

My Prokit has been on since April 2002, so a little more than a year. The drop on my prokit is about 1.5" all around. I did not get after market shocks, not only becuase I didn't want to spend the money but also becuz there was no need for it. I am not into too much handling, I just wanted to get rid of the ugly gap. So you don't necessarily need the springs. BUT if you plan on getting them later get them now becuase it will save you the installation price. They will have to take the springs off anyways to get the shocks on.