rims

i was wandering.... i really like the enkei kapone wheel and i own a 2000 pontiac firebird trans am with ram air. I think these will fit without rubbing but im not sure. Also what offset should i go with. The only make these wheels in a 20 x 8.5. WHat tires should i put on these if they do fit cause i want to have as much rubber as possible on the back. and i think i will have to go with a 30 series tire. any info aprreciated thanks
chris