Just drove for 30 miles on the soft recommended settings (14/14 turns from full stiff, front and rear) and have to say, these ride better than a heavy car with 21" 35-profile tires has any right to be.
Using the "bumpy" scale of my 7 yr old son who rides on booster seat in the back, his numbers (I'm sure these numbers are very subjective
):
1) stock MY P, 42 psi air pressure: 200%
2) after change to Michelin PS A/S 4 tires, 41 psi: 100%
3) after MPP coilovers - initial settings: 59%
4) my last intermediate-soft settings
front 13/16 (compression/rebound turns from full stiff)
rear 12/12 (compression/rebound turns from full stiff)
- 40% "fine"
5) soft settings 14/14
- 6% (quite an improvement)
Unfortunately for him, I do miss the sporty handling (especially on the 21" wheels and Pilot Sport tires), and #4 and #5 are too soft for my preference; I feel my driving confidence on the freeway took a hit (having had my Mazda RX-8, I have a strong bias towards "horse and rider, as one" driving feel) with steering input delayed from the car's motions in my mind. I will tweak the settings further towards initial settings.
For owners that drive a relaxed pace and value comfort over anything else or have to deal with bad roads, and feel strongly that the bad suspension is ruining the Model Y for them, give the 14/14 settings a try. You'll love it.