It really depends on what your alignment looks like already. Dropping the car affects toe the most but also has some effect on the camber. My alignment was all screwed up from the factory so after my first set of tires at 12,000 miles I did the alignment myself. The rear of a cobalt is "not adjustable" according to GM however the rear trailing arm is the same design as the cavalier. If you really want you can have your car set up as a cavalier on the alignment machine and have them install full contact rear shims. One note however the studs that hold the hub to the trailing arm are a little closer together than the cavaliers. All thats needed is to grind the shim a little to make room for the studs. You can change the camber without a kit, you just have to slot the hole in the strut. Its kind of a guessing game as where to lock the strut down but it works. The camber kit offers precise control over the camber because its an eccentric bolt with a bolt head so you can have the strut loose and twist the bolt one way or the other to get your numbers. If your going to get the alignment professionally done let them worry about parts. Also the GM alignment specs are very broad in terms of whats acceptable. If your looking for a specific set of numbers tell them before they start so they have something to shoot for.
2006 LS coupe, manual, Victory Red
Sportlines, FE5 struts, shocks, front swaybar, Progressive 22mm rear swaybar, Airlift load assist rear airbags, TWM ST shifter, smoothed TB, LSJ exhaust, debadged, demudflapped, Yokohama AVID Touring P195/60R15's. Soon to come 17x7 Motegi Tracklight 1.0. Best to date 15.402 at 90mph
"No friend ever served me, and no enemy ever wronged me, whom I have not repaid in full."
Lucius Cornelius Sulla