Whatever you do, make sure it comes apart in 1/2. It's a serious PITA to have a single piece exhaust. And get stainless... with stainless welds, get them to tuck it high, and flatten the pipe where the stock exhaust is flattened, or you'll be rubbing everywhere.
I hate exhaust work, mainly because it costs so much to have it done right, and not end up a beggar.
Performance one step at a time.