I always suspected that 45 psi that Tesla recommends for M3 is a tad high. Although my car doesn't ride that harsh as earlier M3, it is definitely rough than any other car I have had in the past. My 130k miles LX RX 350 rides much more smoother and quieter. Almost all of that is tire noise and I hardly have any wind noise. And then Musk tweeted this: Elon Musk on Twitter I have plenty of range. Too much range for everything except long distance driving. So I am thinking I will reduce the pressure to 40 psi and gladly sacrifice some range for extra riding comfort. Anyone else done this? Do you see any improvement? perhaps a before & after water cup tests are on order ? Most importantly do you foresee any other issues with riding it at 40 psi? perhaps more tire wear?