If you are paying a shop to do the installation and alignment you might as well get the camber kit at the same time. Otherwise you are going to have to pay them again to install it and realign your car down the road. Just my $0.02.
I believe that you will see excessive wear on the inner shoulder of your rear tires even with the drop of the Pro-Kit. I can't say for sure because I'm using the H&R Sport springs and my rear camber is at -2.5ish. However, after I installed my Koni Sports I was on stock springs for a while and I cut down the bumpstops which allowed the rear of the car to sit lower and even with that small decrease in ride height I saw more wear on the inner shoulder of my winter tires. YMMV of course.
And FWIW, an alignment will probably cost you anywhere from $60-100. I recently had it done and it cost me around $90 with tax and everything.