You can get by with just the Pro Kit for a while, but eventually I'd give it a year max, you'll need some new shocks.
I thought the Pro Kit was a great bargain, but it turned out that isn't all you need. You gotta get camber kits, and an alignment, and then later on shocks, so it would probably would be better to just get coilover to start with.
It is more expensive at first, but they will last a lot longer, from what I've read anyway.