I did it Just use ya steering arms from ya Sierra rack on the v6 rack and all is good. You can use the front subframe and mounts. You can use the front arb but it will push the wheels far too forward. the std 28mm front arb should be fine. The whole rear beam inc diff can be used and tbh, I never noticed that the rear had a wider track. Personally I think they are the same. You may have a bit more neg camber on the rear but if you don't go too low with the drop it will be fine. Use the Granny rear arb as its a nice upgrade on the Sierra. As for suspension get yaself some 4x4 legs and rear shox along with v6 springs and the fronts will slot nicely together with the front hubs that will also bolt to your existing Sierra tca's. Bonus with the brakes being bigger too and if you want to be clever keep the 5 stud as this will allow you to run a hell of a lot more choice on wheels.