I installed the quadra steps a long time ago after I got tired of the big step up to my old three stepper. Three steps are not enough on a fifth wheel. It's a very sturdy product I'm a big guy and I can walk up the steps with a big heavy cooler in my hands and the steps yield very little.
Now the installation wasn't that easy because on my rig (and maybe most rigs) not only do the new steps have to be attached to the frame by the sides, the quadra steps need also be supported in the back of the step frame, to the I-beam,due to the longer moment arm of extra step.
I also had to do a lot of modification to where it attaches to the sides (original setup) because the quadra step fits in a little different.
Before I installed it I called up the manufacturer just to ask a few installation questions. I ended up on the phone with the guy who designed it and he talked my arm off! It was a great conversation and he had an answer to every question I threw at him.
I might be wrong but I think that model also comes with a curved step tread which might look a little nicer.