Our newly acquired 2000 Grand Prix GT needs an exhaust. The cat is missing and both of the mufflers are rotted pretty badly. I asked at the pick and pull but he said first thing they do is cut the cats off and throw the exhaust in a scrap pile. There are so many different ones on the internet that I am not sure where to start. We would be happy with a used setup since it's his first car. And the fact that I am funding most of it.What would you guys recommend? Secondly, the wipers keep going when switched off, they do stop eventually, sometimes straight up, sometimes they return to the start position after awhile. Any help appreciated.