Mandrel bent systems are expensive. In my area you can get a beautiful s/s TIG welded mandrel system that is artwork for about 1800.
At this point, I'd recommend TTI systems all the way. I have had several "exhaust shops" do "custom" work for me through the years. They all had one thing in common, they are horrible....Spend the money and do it once. The aluminized will last a good long time.