I just used avery vinyl. I picked up a 8" wide, 200ft long roll of it pretty cheap. The Pre-cut kits **** because you pay the same for them as I did for the whole roll, and if you screw up one piece you are SOL. The curves of the front and rear are a pain in the ass, I layed out the locations, and they used a laser level to project a straight line down the car.
If you were to get a wider sheet of vinyl and cut the pattern into the sheet to make forming it around the curves easier i could suggest the following: measure the stripe locations, setup the laser level projecting the line on the car, mask the line with several layers of tape, layout a paper template over the stripe location (be sure not to move laser), and CAREFULLY cut the paper template with razor and straightedge along the laser line into the protective tape you applied under the paper. Transfer paper template to vinyl, and apply for real.