I'm dropped around 2 inches and the negative camber is close to that if not more. I don't know for sure because I haven't gotten an alignment yet. At any rate you can adjust the 1.5 inches and IMHO it would be good enough, since with 15" you won't need to worry about camber wear all that much, and a little camber is good for turning.

If you plan to do autocross later, it's better to get a camber kit that has more range, since you'll want to camber out more.