Local shop charged me $20 per side to install Flows and put turndowns on them. I had him use the last six inches of my old tailpipes to make the turndowns. From what I have seen posted you don't want dumps, they blow a lot of heat and crap all over your driveline and rear axle. Place turndowns at a 45 angle outward and the exhaust hits the ground right in front of the rear tires. Sounds pretty evil too.
P.S. z9- Dumps come after mufflers, do not affect emissions- simply makes a very short tailpipe.