The Amsoil bypass filter setup that I installed has a restrictor orifice where the filter screws on. This keeps the pressure up. Maybe the older models didn't have this.
At high-idle the oil flows really well.
I used two 8 foot sections of braided stainless aircraft hose to mount the filter on the frame rails under the truck. (Custom made at a local aircraft hose supply company- $80 each, and they have blue anodized fittings to match the blue Amsoil aluminum caps.) It looks great, and my Blackstone reports have been excellent.
I recommend any one of the bypass systems, the Amsoil setup keeps my oil very clean. I'm sure they all work well.