We liked the Bilstein 5125 front and 5165 rear reservoir shock absorbers so much on our last project that we used them again on our 2012 V8 Colorado.
The Bilstein Builder's Series shocks feature gas pressurized monotube construction with a 46mm digressive piston that adjusts instantly to changes in road conditions. The Builder's Series shocks are intended for custom applications. Bilstein does not market this product for OEM applications.
In our application, the 5125 front shocks needed some bottom bushing grinding and the 5165 rear reservoir shocks needed bar pins up top to fit the Chevy, but once the shocks are installed, it's worth it.
The Bilsteins are such a big improvement they make the Colorado a different truck. Compression and rebound damping is perfect and the truck rides and handles great -- both on- and off-road. How can we say this when the 2012 Colorado project doesn't have wheels and tires on it yet? Remember, we already used these identical shocks on our last project.
The shock part numbers for our project, which is a 2012 Chevrolet Colorado with a 4" suspension system, are:
5125 front - #33-186504
5165 rear - #25-176124