When I got my '88 Eagle wagon, last year, the mechanic (who I know) let me slide through PA Inspection with a blown-thru cat. It ran real nice, since there wasn't any back-pressure to the exhaust system.
But, this year, I had to get one. It cost me $135.00 for a universal cat though Advanced Auto Parts. It doesn't run bad. but, there is a difference when you stomp on the pedal. Seems like it runs slower, due to back-pressure.
Wish I could run a burned out Cherry Bomb thru a side pipe.
Steve