Exhaust Pros/Cons for Slant 6

1 header collector, or 2? Either way, I would do single exhaust, decent muffler (though I don't have a rec. on that) then IF you want dual tips, split it. I don't see the point of split pipes just to look balanced, but thats me.
You gain scavenging and I don't think a 2-1/2" pipe is going to choke a slant, and I've never heard a 6 cyl with full duels that sounded good, V's or inlines. I've heard some good sounding jeeps with 4.0, but I wasn't very pleased with the Flow master I put on mine, But I never bothered to ask what others were using.