I'm gonna gather my materials for my set next week. I'll give you guys a materials cost once I'm done. I know it won't be too high. Ballpark figure if i was to make these and sell them would be $300 or under. Xtenzzive's $250 quote sounds about right. It really does cost much in material. The killer part is the labor. Here is a link just so you have an idea of cost.
Exhaust Components They're pricey but you get the idea.