$3500 seems like a lot, but when I was an apprentice painter in a former life(1974), the shop I worked at painted stripes on Vega GTs and Z/28 stripes on Camaros. No templates were used. We'd measure the stripes off factory striped cars and lay them out with tape. There is a lot of prep work involved.
Personally, painted on stripes are the way to go if you can find a more reasonable price. Check out the Mustang Shelbys that use tape stripes. They go around the CHMSL and license bucket. Real cheap looking, IMO, especially on a $50K car.
The way it should be done:
