question on cats, emissions and exhaust

So ive decided on getting downpipes made. does anyone know of a cetrain type of a cat that passes emissions and doesnt cost 500 a peice? i found some cats on magnaflow's site. i'm planning on a full magnaflow setup later down the road for a turboback, but DP's for now. theres a local place that can get parts and do the work. i just need to make sure to get proper cats s i pass, cuz i dont want to pay the extra money for that apr software upgrade that makes the cel's for that go away. maybe theres a cat thats rated for a certain number of cels that i need, im not sure? is there anyone here with a magnaflow setup?