Originally Posted by Pocketfisherman
In the car world on LS1 and LS2 GM motors, the Kooks stainless are the go to brand for real performance gains, good fit, and durability.
I did the Kooks with the 3" catted x-pipe on my LS3 with a tune and gained 39HP & 40 ft lbs TQ through the stock mufflers. Had them Jet Hot coated. They aren't the cheapest but the quality is excellent. Come with a spiked merge collector.