We replaced the OEM springs on our 2019 LE2 (hull 701) with Alcan HD springs a couple of weeks back. Certified RV in Holliston, MA did the work and, other than having a drop link flip as we lowered the trailer off the jacks, the work was done without drama and to our satisfaction.
We then did a 650-mile round trip to the Lehigh Valley to meet up with some friends from Pittsburgh. I re-tightened the bolts after 300 miles and will check them again now that we're home.
Not long after leaving home we felt the HD springs have caused a significant increase in "jounce" (pitch) of the TV, which is a 2019 F-150 SuperCrew, 145" WB, 5'7" bed, FX4 off-road suspension. The TV bed was lightly loaded, perhaps 125 lbs total, with another 50 lbs in the cabin rear seat area. The effect is that the rear of the TV is accelerated upwards when the Ollie hits a large bump, more than we remembered.
Anyone else experience this? Mechanically it makes sense: the Ollie suspension is less compliant, so the hull moves more and transmits this motion to the TV. Something to consider when changing springs... Improved corrosion protection is one thing, increasing stiffness is an entirely different thing.
As a postscript, we recently spoke with a guy at a campground in Morrisville, VT who was pulling a 30' Airstream with a Ford Expedition (not a Max). He insisted that bigger / heavier / more stiffly sprung tow vehicles were not obviously better and mentioned a Canadian YouTuber (name? Too lazy to look) who espoused this view...
We did not change the axles nor replace the equalizers.
Tim