Regarding impact on the wake, we will just have to wait and see. The wife really wanted it for some of the older members of our family who enjoy getting into the water, but struggle to get back in the boat. This is the same ladder that kjkimball used (another thread about it if you search swim ladder).
As far as mounting everything...I took my time, measured and remeasured and again, took my time. Drilling into virgin fiberglass was the most nerve racking element of it and hoping to hell everything lined up and I could get the platform brackets back into slots on the back of the boat. I drilled small pilot holes and then increased the size to accommodate the screws.