This is my 01 GMC Sierra, I bought it in December 2015 with 19xxxx miles for $2600. It came factory with a 4.8 engine and 4L60E connected to a G80 locker with 3.42 gear set. The truck is a long bed and being so it has the HD towing leaf springs rated to 2200 lbs, this of course meant that the back end was 4-inches taller than front.
Mods.

Engine/Drivetrain:
Hayden HD RV cooler/rad cooler bypass.


Suspension:
Rear 2 inch shackless
20X9.5 Synergies GM factory rims on 275/45R20 tires.


Exterior:
4300K HID kit with standalone harness.
Factory style flares

IMG_20180413_181110 by Jesse Gonzalez, on Flickr

IMG_20180413_181342 by Jesse Gonzalez, on Flickr

IMG_20180413_181556 by Jesse Gonzalez, on Flickr

IMG_20180331_165745 by Jesse Gonzalez, on Flickr

On factory 265/70R16

IMG_20180409_152503 by Jesse Gonzalez, on Flickr

On new wheels