btj_z71

You will likely get past 100k and not need new pads or rotors at any corner. If you tow frequently or are a spirited driver, then you *might* need a new pad or need the rotors turned at the front sometime after 100k. My 2014 had 99k miles when I traded it in and never had a brake job. When I change the brake fluid around 80k on that 2014, all pads had plenty of life remaining, and I was not getting any vibration from the rotors. Back to your original question - the Wagner OEx is good product.

Not needed until the temperature drops to 0 or below, or you are at a high elevation. It is listed in the diesel supplement. (See below) Living in southern Alabama, I've never had to use it with my LM2. https://my.gmc.com/content/dam/gmownercenter/gmna/dynamic/manuals/2021/gmc/multimodel/2021-3l-duramax-diesel-supplement.pdf

I'd recommend the Amsoil All-in-one additive. Never had any trouble with it in my LM2. https://www.amsoil.com/p/diesel-all-in-one-adb/

Yep, I did this exact upgrade on my old 2014 silverado. Easy to do at home. No worries on this.

Agreed - change the transfer case fluid and front diff at a minimum. Likely a good bit of metal shavings in there due to the friction of being on pavement.

I'd go get the Amsoil version. Is there some concern surrounding amsoil's dexosD equivalent?

I'm in a 2020 3.0L Duramax now, and would love to have the 2022 upgraded interior. But I think I'll save until the all electric silverado comes out and compare then.

Bosch has always been best for me

No help here, but the microchip shortage has impacted many folks. I am glad I got my LM2 when I did back in August 2020. The LM2 will be worth it though. That 3.0L Duramax paired with the 10-speed is really a dream powertrain. The MPG is great, I can tow and haul everything I need. For example, I rented RVs off of Rvshare.com and one was a 33ft trailer at 7900 lbs with two slides. The LM2 did a great job, especially with the 10-speed there. What I'm most excited to see is the durability of the 3.0L Duramax. I've got just under 11k miles now but I'm excited to get to the 150k mark eventually, and beyond.

I called the GM customer service line to get my sheet. 1-800-462-8782.

Check MAF sensor. Sounds like a sensor wasn't plugged in or is dirty. See if you or a buddy can pull an error code from the ODB port. If not, then you can try taking off the new intake and see if you get any errors with no intake (Just garage test, don't drive w/o a filter on there). If that works, then try putting on the stock or previous intake and see if you get any error. The idea here being to eliminate possibilities of error. I would imagine it's a sensor somewhere knocked loose.

Wagner makes a good product too. No concerns if you went with OEM.

Checkout crutchfield.com, they have great information on speaker upgrades. If all you want is more bass, then just adding a subwoofer would fix that. If your looking for overall sound quality, then the cost to upgrade all the speakers in the truck, it would just make more sense to take back your 2021 and ask for the same truck but with the Bose option. The reason I say this is, aftermarket speakers require more power than your stock head unit can produce. Thus, to get the best sound you would need to add an amplifier as well. Of course, the aftermarket speakers will work but the full benefit of the higher quality speakers would not be realized without the amplifier. Honestly, I just go back to the dealer and get one with Bose in it.

The s20 ultra fits. Not sure about s21. You can keep a short 1ft cable in your truck if it doesn't fit, the Silverado has a USB-C port right next to the wireless charger.

The refrigerant capacity and type is listed in your owners manual, on Google, and listed on your truck's radiator cover. Looks something like the attached image.