They’re fairly small dimensionally. It looks like they’ve upgraded the hardware to back everything up, they used to just use self threading machine bolts and the complaint for a long time was that they would back out after awhile.
What I would do is bolt them in, then take the car to an exhaust shop or something and have them welded in (assuming you don’t have a welder). The bolted connection would be the biggest drawback.
They’re probably not the strongest option out there in terms of results, but they’re way better than nothing. And they’re easier to install, their dimensions mean less interference with hose routing etc. I think they’re a good option for people without access to a welder, or if you have a finished car and don’t want to mess with re-routing fuel and brake lines.