What car and year did your engine come out of? I bought my cats used off of some guy from texas for $50.00 each, its not legal but they work fine. Ive been passing smog since 2004. The most difficult part of the swap will be the exhaust and evaportive emmisions. You might want to make sure the state referees are still around. A couple years ago the reff had closed because of budget restraints, im not sure if they ever reopened.