lerbud

Get a tune. It will fix the wonky 1-2 shift. I used diablosport on my 2016.

Probably. I just tightened them up without over doing it. I have changed the rears on several trucks and have not had any issues...

No special tools needed. Just a socket and a wrench.

4 wheel parts. I ordered last week. I hope to have them in the next few days. They arrived at the warehouse in TX yesterday.

The rears are easy! 30 minute job. The fronts no way! I will have those installed and an alignment done.

I put 5100's on my 2019 RST and it has helped quite a bit. I have the fronts on order.

These are the ones I have: https://accessories.chevrolet.com/product/crew-cab-second-row-interlocking-premium-all-weather-floor-liner-in-very-dark-atmosphere-84333636?year=2020&make=Chevrolet&model=Silverado 1500&modelId=491&body=Crew Cab Pickup&bodyId=22&wheel=Short Box&wheelId=651&trim=RST&trimId=4962&drive=4WD&driveId=8&engine=5.3L V8 GAS&engineId=2059&bodyNumDoors=5

This should help you out:

https://www.gmpartsonline.net/v-2015-chevrolet-silverado-1500--ls--4-3l-v6-flex/body--tailgate

See if this helps:

These are nice. I bought a set of black ones from him a while back.

Bumper removal : https://www.gmfullsize.com/threads/front-chrome-bumper-slots.214684/

Not hard just a pain. Need to remove the grill and then the bumper. The bumper has lots of 10 mm bolts holding it together. Grill removal:

It could be the rear headrests making noise. Fold them down and see if that fixes it. If that works spread the headrest posts out a little and reinstall.

These are the seat covers I bought. They have a GM part# on each piece so it was easy to match up since there are no instructions. No special tools needed to install. Everything these days clips or zipppers in place. The hardest job to me is the front headrest cover install. The rear headrests were super easy. https://www.ebay.com/itm/2019-2020-NEW-TAKEOFF-OEM-CHEVROLET-SILVERADO-CREW-CAB-LEATHER-SEAT-COVER-SET/223803853359?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649