I had my tint done at a place called tintwerks near ala moana..................15% all around and 35% on the windshield. Of course it's not legal though. Heard Al's Tinting in Peral City is pretty good, I would try and give them a call.
I went to protint in Kalihi, was $160. They did an excellent job. BTW, the legal limit is 35% but they allow a margin of error in the readings so if you measure above 30% then they will usually let you slide. Mine read at 33% on 35% film, so you might be pushing it if you get 30% film.