Hello,
I'm looking at the Dana marine system are they a good system and how long do they last in fresh water?

No, the Dana Marine exhaust is not a good system, it's a GREAT system. Performance is almost as good as comparable size tubular headers and none of the potential problems. (cracks, welds, joints, etc.) Best money I ever spent on my boat.

Some good reading here http://www.fullthrottlemarine.com/ Go to view high performance projects.

Plane Silly, thanks for the link that is exactly what I was looking for.

Nice exhaust, quality design, good bling factor.