yup and the guys at VRSF pointed out to me yesterday, it says "up to the flange" Meaning that the flange is 2.5 inches at its opening, and the tubing tapers to that right where the flange is welded.
Essentially they are trying to be very sneaky and somewhat con you into thinking theirs is better from their wording. But honestly, an inch difference in terms of where it tapers isn't gonna make any noticeable difference. Maybe .1 horsepower. If it tapers, it tapers... and inevitably causes a restriction. So as far as I'm concerned they are all the same. Only difference is build quality and material choice. And from what i've seen there is absolutely no reason to buy $899 downpipes when the $329 downpipes are made outta the stainless steel, and probably fit just fine.
Tho there are some people out there that buy the $899 downpipes just so they can say they spent $899 on downpipes.