Is different, beefier like they say, and who knows, could be a different material. It's pretty obvious they are aware of the V2 problem, not likely they'd ignore it while making everything else better. V2 mechboxes almost always break on the right side shell (ever notice how the left side of the cylinder head is always tighter in the mechbox than the right?). First (and only one) I've seen break on both sides was when my stock MP5 shell broke. And look at where the screws go through, they are raised to mate with the right shell, which will give a lot more strength to the right shell, since the left will suffer as much abuse as the right.