Stainless would be the best option. I just replaced the exhaust on my mother's XJ a couple of weekends ago. It isn't terrible hard to do. I got it done in about 5hrs. We were in a pinch at the time so I just bought a $100 one off eBay and was actually surprised with the quality. It came with the int/exh gasket and a new flange gasket for the collector. If it only lasts a couple of years, I'll be happy.