I have Billet Specialties Street Lite rims on my car in the 15x4 with 2.25BS on the front of my car. I don't like the deeper dish on the outside of the rim even though it's only .625 deeper. I really should be running about a 5" wide rim so that's why I went with the 4".
I have some Cragar 15x4s one car and Sprints 15x3.5s on another. I agree about going with the wider of the two and also about an offset that keeps the tires tucked in. The further they stick out the higher the loads on them. These are really too narrow for the street, but.... On another, I was able to get what is probably the best, 15x5, on a set of custom steel Rally wheel from Vintiques.