PhatSS10
I can answer any specific questions you might have, I swapped out my 99 S10 front end on to a Envoy, i'm running the entire front end HID's and all.
You'll need the following parts
GMC Grille Shell (paintable or chrome)
GMC Impact bar (face bar it's the metal behind the bumper cover)Envoy Bumper brace bars
HID Resitor(ballast) Support Brackets (left and right)
Envoy Lamp Assemblys w/HID resistors (left and right) approx 750 from parts.com
Envoy Bumper Cover
Chrome strips for the Envoy cover.
Foam Bumper cover spacers (they get inserted between the bumper cover and face bar under the headlights)
Billet or Speed grilles for the GMC grille shell and envoy bumper cover.
You'll also need the Envoy Fog light or you can use aftermarket fogs, i used the pilots but i don't really like how they fit. So you may want to try and purchase the actual envoy fogs.
You'll be able to use all the existing bolts and clips from your old chevy front end for the envoy front end for the most part. It's a day long project pretty much from morning to night. But it's well worth it when you finish and it looks hella cool at night when u pass those expensive luxury cars with HIDs at night lol
I only have one bug with my swap at the current time, and that's during the day the HID's stay on with the DRL's for some reason but at night they work like they should, the DRL's turn off and it's all good. I'm still looking into that, a friend says he knows how to fix it but who knows he's busy as hell so i've just run the truck with the night lamps (HID's) turned on all the time.
Let me know if you have any questions, and if you decided to do the swap I can help you with installation questions a little.