I moved to colarado a few years ago and have a 2wd 2003 Silverado. I had thought about trading it in for a 4wd, but i own my truck and dont really want another bill. What is more difficult putting a 4wd conversion or the awd system from the trailblazer?

 

You'll likely need a new ECM to convert to a 4x4, You will also need to swap out the front end with a 4x4 axle, the Silverado uses an NV-246 TC and the trailblazer uses an NV-226 TC, Then you have all the wiring to do, driveshaft modifications, ect