These days I go OEM parts unless I've seen and tested the aftermarket part in person. OEM parts are like the waterfall development model in software engineering: it's boring, but it's dead simple, and it works.
I feel like every single non-OEM part that I've purchased has had some minor fitment issue that ruins it. Cheapo window switches? Different shape and font though claiming part compatibility. Tow mirrors? Either there is no physical way for me to see behind the vehicle, or, they don't stop short of the door, meaning that when some moron at the garage slams them closed I get a fresh dent on my door. Radios? The fitment is often poor, factory buttons don't work, and all sort of little things don't line up.
For the most part the engineers at GM did their job. Sometimes they didn't (don't get me started on broken door handles). But a fine vehicle is a system, everything needs to work together.
I'm sure GM's brake guidelines are based on real world testing, in different temperatures, with different loads up to and past GVRW. They selected the components they did for a reason. These things go in cop cars, ambulances, and the like.
I'm into airplanes too. One of my favorite videos is the Airbus A380 brake certification tests. They take brand new tires and file them down to be exactly at their minimum allowable thickness for takeoff. They do the same to the brake pads and the brake discs. Then, they fill the plane up to maximum weight (fuel plus ballast), put it on the shortest, most downhill runway allowable at max weight, wait for no wind, and abort a takeoff at the last possible instant. The plane has to stop short of the end of the runway AND remain standing for five whole minutes. The brakes and wheels catch fire doing this - they're write offs - but it works.
I don't know that GM did this with our trucks. Maybe? Would be great to see it.
On trucks, like on bicycles, I don't screw around with brakes.
