Opening up the ports is indeed an involved task and with many "more modern" machines, there's internal duct/hose that plays into the equation. I think that it's too bad that the defacto standard for so many machines is 4" whereas 5"/120mm is a better average for good air flow performance, especially for machines with larger capacities which is a lot more common now, even in small shops. And yes, 6"/150mm can really rock on the larger machines for sure. But "back in the day", dust collectors were a new thing and I guess 4" got the nod, at least in North America, and it's continued to stick. Oh, well...