First off ALL of these trucks have the exact same problem with the brake lines. In addition to the trucks many of the GM cars and other manufacturer cars have the SAME problem as well. I do not recall the exact years but it was like from 1997-2007 if I recall correctly . GM and other manufacturers decided NOT to use stainless steel brake lines AND they also chose not to paint, plate or coat the brake lines. Probably some money saving issue?? So almost EVERY one of these vehicles is at a severe risk. Maybe vehicles that live in the Southwest US may be fine, but others are DANGEROUS. If the lines do not appear to have been replaced, they NEED to be replaced.
Then there is the OTHER problem! The rear brake backing plates are also a disaster on these vehicles. They rust out faster than the brake lines!!!!! The parking brake will not operate properly and the backing plates can and will collapse. These are fairly cheap, but you need to drain the rear differential and pull the axles to replace the backing plates. Trust me, if you have a Northern truck, you have RUST on the brake lines and the rear brake backing plates are shot unless you are lucky and someone has replaced them.
Then the last item. I do not get where you are coming from on the exhaust manifold bracket/clamp. They work fine. Matter of fact they have been on my truck for about 2 years. In replacing the brake lines on my truck I found the drivers side manifold had 2 more broken bolts, the very front and one in the middle somewhere.
I pulled the manifold but I am still going to use the clamp for the rear most bolt for 2 reasons. 1 you cannot access the rear bolt while the engine/head is in the vehicle and 2 the rear most bold broke off flush with the head so I cannot easily grab onto the bolt in anyway. Plus I would have to go to all the effort to remove the clamp as well.
I really think you need to LISTEN and LEARN about these trucks, I am sure MANY, MANY people on this forum and others have all had problems with their brake lines, rear brake backing plates and exhaust manifold bolts!
Do what you want, but do not say you were not warned.