Sneak Peek is an absolutely awful, awful figure. I never even knew he existed until a few years ago. Maybe if I'd had him as a kid, he'd work better in my head. But he looks like Porkins from Star Wars, and while I'm a bit of a fatass myself, I don't see a team like GI Joe having lardasses on their team.
With that said, and knowing that I really hate the character and his design, I think you did a great job creating a new version of him. I kind of prefer the darker color, to be honest.
He's a dreadful design, but you made him look pretty cool. The way you added the collar to the stubbier body build still gives that stockier image, but without leaving him looking like a butterball like the original. It actually works.