5.3 2013 Silverado
I play proball and my buddy on my team has the doug thorley longtubes on his 09 6.2 silverado and he talked about it helping more with Power than even his Tuner. He wasn't lying. As far as installation goes. Just take your time and do it right. Take a day and do it right and it's not bad at all. Once you get the stock headers off putting the new ones on is not bad. Use PB blaster to loosen old headers. Much easier after
Amazing - very satisfied.
I have put on several sets of headers over the years and it has always been a fight. My stock toyota manifold had cracked into two pieces and I had the choice of spending the same amount of money on a manifold from toyota or the headers. I opted for the headers and the install was actually easier than the removal. I would have never guessed that it would be that straight forward. Performance it seems that my mileage is up slightly and the engine rev's more freely up to the 6000+ RPM range.