Hi John, can not help with the pipe restriction as our Plus Six does not have this, due i suspect to the wider body on the six.
We do still have the issue of crud and water impacting the lower 5th of the filter, we still have the standard filter but i change it yearly, in an attempt to reduce the water getting in, i cleaned the bottom filter access plate then ran a very small bead of silicon sealant around its edges and let it set. This gives the plate a bottom seal. It helps the water issue, but the crud still enters via the filters side feed.
I dont use locktite on the lower plates bolts, but use copper grease. Never had a bolt come loose yet.
